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Stimulating the Ventrolateral Prefrontal Cortex (VLPFC) Modulates Frustration-Induced Aggression: A tDCS Experiment
Abstract
Background:
The prefrontal cortex is crucial for top-down regulation of aggression, but the neural underpinnings of aggression are still poorly understood. Past research showed the transcranial direct current stimulation (tDCS) over the ventrolateral prefrontal cortex (VLPFC) modulates aggression following exposure to risk factors for aggression (e.g., social exclusion, violent media). Although frustration is a key risk factor for aggression, no study to date has examined the modulatory role of tDCS on frustration-induced aggression.
Objectives:
By exploring the VLPFC involvement in frustration-aggression link, we tested the hypothesis that the anodal tDCS over right and left VLPFC modulates frustration-induced aggression. We also explored whether tDCS interacts with gender to influence frustration-induced aggression.
Methods:
90 healthy participants (45 men) were randomly assigned to receive anodal or sham tDCS over the right or left VLPFC before being frustrated by an accomplice. To increase reliability, several tasks were used to measure aggression.
Results:
We found that anodal tDCS over the left VLPFC, compared to sham stimulation, increased aggression. Unexpectedly, no main effect was found following tDCS of right VLPFC. However, we also found a significant interaction between gender and tDCS, showing that males were more aggressive than females following sham stimulation, but females became as aggressive as males following active tDCS.
Conclusion:
Overall, these results shed light on the neural basis of frustration-induced aggression, providing further evidence for the involvement of VLPFC in modulating aggressive responses, and on gender differences in aggression. Future research should further investigate the role of stimulating the VLPFC on frustration-induced aggression.
... Six studies measured the impact of NIBS to the VLPFC (Chen, 2018;Gallucci et al., 2020;Riva et al., 2015Riva et al., , 2017 or partly affecting this PFC region (Dambacher et al., 2015b;Smits et al., 2022). All the studies that included self-reports for measuring changes in anger state after applying Table 1 Summary of characteristics of the studies assessing the effects of non-invasive brain stimulation techniques in the dorsolateral and dorsomedial prefrontal cortices, as well as prefrontal cortex, alphabetically ordered by first author's surname. ...
... Nonetheless, those which measured aggressive behavior with laboratory tasks offered mixed results. Two studies failed to report significant changes (Riva et al., 2015;Dambacher et al., 2015b) and the other three concluded that NIBS promoted significant changes in aggressive behavior (Chen, 2018;Gallucci et al., 2020;Riva et al., 2017). Accordingly, it seemed that the anodal stimulation of the right VLPFC reduced aggression in laboratory tasks (Chen, 2018;Riva et al., 2017), but the stimulation of the left VLPFC increased the aggression of healthy young adults (Gallucci et al., 2020) (Table 2). ...
... Two studies failed to report significant changes (Riva et al., 2015;Dambacher et al., 2015b) and the other three concluded that NIBS promoted significant changes in aggressive behavior (Chen, 2018;Gallucci et al., 2020;Riva et al., 2017). Accordingly, it seemed that the anodal stimulation of the right VLPFC reduced aggression in laboratory tasks (Chen, 2018;Riva et al., 2017), but the stimulation of the left VLPFC increased the aggression of healthy young adults (Gallucci et al., 2020) (Table 2). Regarding the stimulation of the VMPFC, only three studies were finally included, although none of them clarify the specific region of the stimulation (e.g., left, right or bilaterally). ...
Since the 1990s, there has been a rise in the number of publications assessing the effects of applying non-invasive brain stimulation (NIBS) to treat patients with drug-resistant depression. This involves applying magnetic fields or electrical currents to the surface of the skull to influence the superficial neurons in the cerebral cortex. Due to the evidence regarding symptom reduction in these types of patients, such as irritability or hostility, there was a rise in the use of this technique to reduce negative mood, including anger state. This decrease in anger state could also help reduce other problems such as violence proneness. In this sense, the anger state of individuals who are prone to violence might be affected by interfering with the excitability of the prefrontal cortex (PFC), a key brain region responsible for behavioral regulation. Thus, we conducted a systematic review and meta-analysis following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) criteria. After initially identifying 2426 sources, we eventually included a total of 69 publications for the systematic review, from which 45 were employed for the meta-analysis. Only a few of them highlighted a significant contribution of using NIBS techniques on different regions of the PFC to reduce anger state or violence when compared to participants receiving sham stimulation in normative and clinical samples. Furthermore, the comparison of effect sizes between groups that received real stimulation on several regions of the PFC and those that received sham stimulation did not reveal a significant difference in reducing anger state or violence. In addition, despite most of the conclusions being consistent, considerable heterogeneity existed across studies regarding certain PFC regions, which could be explained by the type of NIBS employed. Therefore, using superficial stimulation over the PFC as a general tool for reducing violence proneness should be approached with caution, except in specific cases.
... In a study conducted by Gallucci et al. [183] with 90 healthy volunteers, the aim was to investigate the effects of single-session tDCS over the VLPFC on frustration-induced aggression. The participants completed online measures of anger and aggression (Trait Anger Scale, BP-AQ) prior to the neurostimulation session. ...
... The remaining fifteen studies carried out a between-subjects design (comparing active and sham stimulation in different groups). Ten of them found a statistically significant aggression reduction [178,181,182,[189][190][191]194,195,197,206], two of them found a statistically significant aggression increase [183,188], and three did not find any statistically significant effect [185,186,203]. ...
... Of the eight single-blinded studies, five found a statistically significant aggression reduction [178,181,182,189,195] and two found a statistically significant aggression increase [183,199], whereas one did not find any statistically significant effect [185]. ...
Intro: Aggressive behavior represents a significant public health issue, with relevant social, political, and security implications. Non-invasive brain stimulation (NIBS) techniques may modulate aggressive behavior through stimulation of the prefrontal cortex. Aims: To review research on the effectiveness of NIBS to alter aggression, discuss the main findings and potential limitations, consider the specifics of the techniques and protocols employed, and discuss clinical implications. Methods: A systematic review of the literature available in the PubMed database was carried out, and 17 randomized sham-controlled studies investigating the effectiveness of NIBS techniques on aggression were included. Exclusion criteria included reviews, meta-analyses, and articles not referring to the subject of interest or not addressing cognitive and emotional modulation aims. Conclusions: The reviewed data provide promising evidence for the beneficial effects of tDCS, conventional rTMS, and cTBS on aggression in healthy adults, forensic, and clinical samples. The specific stimulation target is a key factor for the success of stimulation on aggression modulation. rTMS and cTBS showed opposite effects on aggression compared with tDCS. However, due to the heterogeneity of stimulation protocols, experimental designs, and samples, we cannot exclude other factors that may play a confounding role.
... In another study, the anodal stimulation to the rVLPFC reduced the unprovoked (but not the provoked) aggression that followed playing violent video games (Riva et al., 2017). A more recent study focused on one of the main causes of aggression: frustration, which was induced in participants by means of an unsolvable task on number sequences (Gallucci et al., 2020). Aggression was then measured by means of three behavioral tasks (e.g., giving noise blasts in the headphones to a partner in a competitive task). ...
... For this reason, DLPFC should also be considered in relation to its projections to striatum, which is implicated in action selection (Buckholtz, 2015). The specific localization targeted by an intervention should also be carefully considered given that the reviewed results from studies using tDCS suffer the limitation of this technique in terms of low spatial resolution (e.g., Gallucci et al., 2020;Riva et al., 2012). Thus, more focal techniques, such as rTMS, would provide more specific localizations. ...
... Finally, screenings should consider individual differences based on gender as electrophysiological evidence about the neural mechanisms of empathy has shown some differences between psychopathic males and females (Saladino et al., 2021). Furthermore, as previously mentioned, gender differences in aggression were also found following sham stimulation, but not when following tDCS stimulation (to either hemisphere) in a sample of healthy adults (Gallucci et al., 2020). ...
Non-compliance with social and legal norms and regulations represents a high burden for society. Social cognition deficits are frequently called into question to explain criminal violence and rule violations in individuals diagnosed with antisocial personality disorder (APD), borderline personality disorder (BPD), and psychopathy. In this article, we proposed to consider the potential benefits of non-invasive brain stimulation (NIBS) to rehabilitate forensic population. We focused on the effects of NIBS of the prefrontal cortex, which is central in social cognition, in modulating aggression and impulsivity in clinical disorders, as well as in forensic population. We also addressed the effect of NIBS on empathy, and theory of mind in non-clinical and/or prison population. The reviewed data provide promising evidence on the beneficial effect of NIBS on aggression/impulsivity dyscontrol and social cognitive functions, suggesting its relevance in promoting reintegration of criminals into society.
... In the selected studies, various behavioural aggression paradigms were used: the Taylor Aggression Paradigm (TAP) [11], the Competitive Reaction Time Task (CRTT) [44], the Aggression Infused Ultimatum Game [13], the Voodoo Doll task [12], the Sequence Choosing Task [45], the Tangram Task [45], the Hot Sauce Paradigm [46], and the Social Orientation Paradigm task [27]. As an alternative to behavioural aggression assessment tasks, some studies employed self-report instruments such as the Buss-Perry Aggression Questionnaire [47] and the Reactive Proactive Aggression Questionnaire [6] to measure aggression. ...
... In the selected studies, various behavioural aggression paradigms were used: the Taylor Aggression Paradigm (TAP) [11], the Competitive Reaction Time Task (CRTT) [44], the Aggression Infused Ultimatum Game [13], the Voodoo Doll task [12], the Sequence Choosing Task [45], the Tangram Task [45], the Hot Sauce Paradigm [46], and the Social Orientation Paradigm task [27]. As an alternative to behavioural aggression assessment tasks, some studies employed self-report instruments such as the Buss-Perry Aggression Questionnaire [47] and the Reactive Proactive Aggression Questionnaire [6] to measure aggression. ...
... The number of difficult puzzles chosen is the measure of aggression. The Sequence Choosing Task is a validated tool to measure aggression [45]; the Tangram Task is similarly well-validated, and has good convergent and discriminant validity [54]. ...
Aggressive behaviour is at the basis of many harms in society, such as violent crime. The efforts to explain, study, and possibly reduce aggression span various disciplines, including neuroscience. The specific brain networks which are involved in the modulation of aggressive behaviour include cortical asymmetry and brain areas such as the dorsolateral prefrontal cortex (DLPFC), the ventrolateral prefrontal cortex (VLPFC), and the ventromedial prefrontal cortex (VMPFC). Recent non-invasive brain stimulation (NIBS) research suggests that both transcranial direct current stimulation (tDCS) and continuous theta burst stimulation (cTBS) can play a role in the modulation of aggressive behaviour by directly changing brain activity. In this review, we systematically explore and discuss 11 experimental studies that aimed to modulate aggressive behaviour or self-reported aggression using NIBS. Out of these 11 studies, nine significantly up- or downregulated aggression by using tDCS or cTBS targeting the DLPFC, VLPFC or VMPFC. The potential applications of these findings span both the clinical and the forensic psychological domains. However, the results are limited by the methodological heterogeneity in the aggression measures used across the studies, and by their generally small sample sizes. Future research should consider improving the localization and specificity of NIBS by employing neuro-navigational instruments and standardized scoring methods.
... It is interesting to highlight that both studies mainly stimulated the prefrontal cortex (PFC), which has usually been associated with behavioural control [79]. Nevertheless, most of the studies that also stimulated the PFC failed to report significant anger-state or irritability improvements after the application of these techniques [24][25][26][27][29][30][31][32][33][34][35][37][38][39][40][41][42][43][44][45][46][48][49][50][51][52]54,57]. The rest of the studies focused the brain stimulation on the left temporo-parietal junction [36], vermis and cerebellar hemispheres [56], inferior frontal cortex [47], and earlobes [55], but they also failed to reduce anger. ...
... With regard to violence proneness measured by laboratory tasks, most of the studies included revealed significant and relatively similar results. Furthermore, it is interesting to note that these studies measured violence proneness with a well-validated computer task, the Taylor Aggression Paradigm (TAP) [41,47,48,54,[61][62][63][64]. On this task, participants compete with a virtual opponent, and they must respond to a provocation (fictitious character/opponent). ...
... This test makes it possible to manipulate the degree of provocation and assess the participants' perception of provocation and their type of aggressive reaction (reactive or proactive). Finally, it is also important to keep in mind that all the studies included a sham-group as controls, and some of them were double-blinded [41,54,60,63]. ...
The field of neurocriminology has proposed several treatments (e.g. pharmacological, brain surgery, androgen-deprivation therapy, neurofeedback…) to reduce violence proneness, but unfortunately their effectiveness has been limited due to their side-effects. Therefore, it is necessary to explore alternative techniques to improve patients’ behavioural regulation with minimal undesirable effects. In this regard, non-invasive brain stimulation techniques, which are based on applying changing magnetic fields or electric currents to interfere in the cortical excitability, have revealed their usefulness in alleviating the symptomatology of several mental disorders. However, to our knowledge, there are no reviews that assess whether these techniques are useful for reducing violence proneness. Therefore, we conducted a systematic review following PRISMA criteria using the following databases: PsycINFO, PubMed, Dialnet, Psicodoc, Web of Knowledge, and Cochrane Library. We initially identified 3746 entries and eventually included 56 publications. Most of the studies were unanimous in concluding that the application of these techniques over the prefrontal cortex (PFC) was not sufficient to promote anger and irritability reductions in euthymic individuals of both genders. Nevertheless, the application of non-invasive brain stimulation techniques, especially transcranial direct current stimulation, over the right PFC seemed to reduce violent reactions in these individuals by interfering with the interpretation of the unfavourable situations (e.g. threating signals) or inner states that evoked anger. In antisocial and pathological populations, the conclusions were provided by a few pilot studies with important methodological weaknesses. The main conclusion of these studies was that bilateral stimulation of the PFC satisfactorily reduced anger and irritability only in inmates, patients with autism spectrum disorders (ASD), people who suffered a closed-head injury and agitated patients with Alzheimer’s disease. Moreover, combining these techniques with risperidone considerably reduced aggressiveness in these patients. Therefore, it is necessary to be cautious about the benefits of these techniques to control anger, due the methodological weaknesses of these studies. Nonetheless, they offer valuable opportunities to prevent violence by designing new treatments combining brain stimulation with current strategies, such as psychotherapy and psychopharmacology, in order to promote lasting changes.
... Indeed, when prefrontal regions are stimulated, tDCS is assumed to slightly improve several functions related to executive functioning [19, [33][34][35][36]. Additionally, systematically matching a No-Go response with motivational content reduces its positive valence [37,38]. ...
... Additionally, the synergistic effect found is consistent with the view that AUD results from poor inhibitory control over alcohol-related responses [7,10-12,32]. Indeed, when the prefrontal regions are stimulated, tDCS is assumed to modestly improve specific functions of executive control (e.g., response inhibition, enhanced response accuracy in online tasks, reduced aggression) [33][34][35][36]56]. On the other hand, motor response training via a specific Go/No-Go task might modify behavior by changing the explicit attraction towards an object [37,38]. ...
Background
Approximately half the people with alcohol use disorder (AUD) relapse into alcohol reuse in the few weeks following withdrawal treatment. Brain stimulation and cognitive training represent recent forms of complementary interventions in the context of AUD.
Objective
To evaluate the clinical efficacy of transcranial direct current stimulation (tDCS) over the dorsolateral prefrontal cortex (DLPFC) combined with alcohol cue inhibitory control training (ICT) as part of rehabilitation.
Methods
A randomized clinical trial was conducted on patients (n=125) withsevere AUD at a withdrawal treatment unit. Each patient was randomly assigned to one of four conditions, in a 2 [verum vs. sham tDCS] x 2 [alcohol cue vs. neutral ICT] factorial design. The primary outcome of the treatment was the measured abstinence rate after two weeks or more (up to one year).
Results
Verum tDCS improved the abstinence rate at the 2-week follow-up compared to the sham condition, independently of the training condition (79.7% [95% CI = 69.8-89.6] vs. 60.7% [95% CI = 48.3-73.1]; p = 0.02). A priori contrasts analyses revealed higher abstinence rates for the verum tDCS associated with alcohol cue ICT (86.1% [31/36; 95% CI= 74.6-97.6]) than for the other three conditions (64% [57/89; 95% CI = 54-74]). These positive clinical effects on abstinence did not persist beyond two weeks after the intervention.
Conclusions
AUD patients who received tDCS applied to DLPFC showed a significantly higher abstinence rate during the weeks following rehabilitation. When combined with alcohol-specific ICT, brain stimulation may provide better clinical outcomes.
Trial Registration
ClinicalTrials.gov number NCT03447054
... Indeed, when prefrontal regions are stimulated, tDCS is assumed to slightly improve several functions related to executive functioning [19,[33][34][35][36]. Additionally, systematically matching a No-Go response with motivational content reduces its positive valence [37,38]. ...
... Additionally, the synergistic effect found is consistent with the view that AUD results from poor inhibitory control over alcohol-related responses [7,[10][11][12]32]. Indeed, when the prefrontal regions are stimulated, tDCS is assumed to modestly improve specific functions of executive control (e.g., response inhibition, enhanced response accuracy in online tasks, reduced aggression) [33][34][35][36]56]. On the other hand, motor response training via a specific Go/No-Go task might modify behavior by changing the explicit attraction towards an object [37,38]. ...
- Multiple sessions of tDCS targeting the DLPFC reduced the rate of early relapse in detoxified patients with alcohol-use disorder.
- When tDCS is combined with alcohol cue inhibitory control training, the abstinence rate at two weeks after discharge was the highest.
- The resilient effects of the combined procedure on abstinence did not persist beyond one month after the intervention.
- tDCS associated with alcohol cue inhibitory control training could be an efficient complementary intervention during alcohol withdrawal treatment.
... Aggressive behavior was assessed through the tangram task , which has been validated as an accurate assessment of hurtful behavior in a research paradigm (Gallucci et al., 2020;Saleem et al., 2017;Van Damme et al., 2017). In addition, this task is not significantly different from the hot sauce task (McGregor et al., 1998) in measuring hurtful behavior and is highly correlated with the competitive reaction time (RT) task (Warburton & Bushman, 2019), two commonly used measures of aggression (Gallucci et al., 2020;Saleem et al., 2015). ...
... Aggressive behavior was assessed through the tangram task , which has been validated as an accurate assessment of hurtful behavior in a research paradigm (Gallucci et al., 2020;Saleem et al., 2017;Van Damme et al., 2017). In addition, this task is not significantly different from the hot sauce task (McGregor et al., 1998) in measuring hurtful behavior and is highly correlated with the competitive reaction time (RT) task (Warburton & Bushman, 2019), two commonly used measures of aggression (Gallucci et al., 2020;Saleem et al., 2015). This task involves participants assigning tangram puzzles to an ostensible other participant. ...
Video game depictions of racial minorities are often stereotyped and likely to activate aggressive schema and behaviors. Using the theoretical framework of Proteus Effect, we manipulated the avatar race (White or Black) of main and enemy characters in a video game as well as the race of a partner in an aggressive behavior task. This allows for a more complete test of how mediated intergroup aggression translates to behavior in the real world. For White participants, a significant 3-way interaction between the race of the main character, enemy character, and real-world partner emerged. Specifically, participants were more aggressive toward White partners in intergroup conditions compared to same-race conditions. A similar pattern of results was found for motivations to harm the real-world partner. We discuss the possibility that violent intergroup scenarios in video games may influence aggression in some real-world situations.
... In general, a decrease in aggression is most likely to occur via the excitatory stimulation of the right prefrontal areas, whereas increased aggression is more likely to occur by increasing the excitability of the left prefrontal cortex-in accordance with the Sutton and Davidson (1997) model. A review by Casula et al. (2023) has reported that 6 of 11 brain stimulation studies on healthy individuals-ten of which employed tDCS-obtained a decrease in aggressive behavior (Chen, 2018;Choy et al., 2018;Dambacher et al., 2015a;Gilam et al., 2018;Riva et al., 2015Riva et al., , 2017, three studies observed an increase (Gallucci et al., 2020;Hortensius et al., 2012;Perach-Barzilay et al., 2013), and two studies did not find any effect (Dambacher et al., 2015b;Ling et al., 2020). It was also reported that the anodal stimulation of the vlPFC, dlPFC, or mPFC of the left hemisphere could increase aggression (2/2 experiments), whereas the same stimulation applied to the right hemisphere decreased aggression (6/8 experiments). ...
A growing body of evidence has shown the key role of the dorsolateral prefrontal cortex (dlPFC) in aggressive behavior, along with the chance of modulating it by means of transcranial direct current stimulation (tDCS). However, the functional interplay between the two cerebral hemispheres in the regulation of aggressive behavior is still unclear. To address this issue, we assessed the effect of bi-hemispheric prefrontal tDCS in 76 healthy adults with a cross-over, double-blind, sham-controlled design. Half of the participants received the anodal stimulation over the right dlPFC and the cathodal stimulation over the left dlPFC (right anodal/left cathodal; Experiment 1), whereas the other half received the anodal stimulation over the left dlPFC and the cathodal stimulation over the right dlPFC (right cathodal/left anodal; Experiment 2). During tDCS, participants underwent the Point Subtraction Aggression Paradigm. All participants were also given self-report questionnaires measuring individual levels of aggression, impulsivity, and empathy to test whether these constructs were associated with the neuromodulation of aggressive responses at the Point Subtraction Aggression Paradigm. Results show a significant increase in aggressive reactions to provocation during right anodal/left cathodal prefrontal tDCS only within males, highlighting a sex-specific effect of the prefrontal neuromodulation that is also associated with individual levels of aggression. These findings provide a new insight into the brain mechanisms that regulate aggressiveness, their sex differences, and their association with dispositional aggressive tendencies.
... The well-documented importance of mPFC in the control of aggression (Gallucci et al., 2020;Giancola, 1995;Raine et al., 2000;Takahashi Fig. 5. Post-weaning social isolation leads to deficient SERT density changes following aggressive interaction. A, Experimental design. ...
Aggression is a complex behavior influenced by developmental experiences, internal state, and social context, yet its neurobiological underpinnings remain insufficiently understood. The serotonergic system, particularly the serotonin transporter (SERT), plays a crucial role in aggression regulation. Here, we investigated region-specific, dynamic changes in SERT expression following aggressive interactions and in mice subjected to early-life social adversity. We found that aggressive encounters (resident-intruder test) triggered a significant, rapid increase in SERT immunoreactivity within 90 min, accompanied by neuronal activation in aggression-related brain regions, including the medial prefrontal cortex (mPFC), lateral septum (LS), medial amygdala (MeA), ventromedial hypothalamus (VMHvl), lateral habenula (LH), and dorsal raphe (DR), but not in the paraventricular thalamus (PVT). Notably, this SERT upregulation occurred across the aggression circuitry but was accompanied by a significant increase in 5-HT levels only in the mPFC, a key region in top-down regulation of social and aggressive behavior. This SERT upregulation was not observed following exposure to a non-social challenge, suggesting that it may be more specifically associated with social contexts. Using super-resolution microscopy, we identified an increased density of SERT localization points within serotonergic mPFC axons after an aggressive encounter. Social isolation during adolescence, a model of early social neglect, impaired this rapid SERT response, particularly in the ventral and medial orbitofrontal regions, and altered the relationship between SERT levels and aggression-related behaviors. These findings demonstrate that SERT expression undergoes rapid, experience-dependent plasticity in response to social aggression, and that early-life adversity disrupts this adaptive mechanism, providing new insights into the serotonergic regulation of aggression and its potential relevance for stress-related social dysfunctions.
... The vlPFC is a crucial hub for top-down emotion regulation, particularly in managing impulsive behaviors and mitigating aggression triggered by frustration or other negative stimuli. Anodal tDCS to the left vlPFC heightened aggressive responses, with no effects observed for sham stimulation, while the right vlPFC showed no significant influence, indicating hemispheric specificity [92]. Gender differences further underscored the complexity of the vlPFC's regulatory role, as males exhibited higher baseline aggression under sham conditions, while females' aggression levels increased under active stimulation, reaching those of males. ...
Perceived social support is recognized as a critical protective factor against the development of mental health disorders. Anxiety disorders are the most common group of mental health disorders and have a substantial impact on individuals' well-being. Despite extensive research on anxiety and perceived social support, a significant gap exists in our understanding of the neural mechanisms linking these two phenomena. While several brain regions, including the amygdala, hippocampus, and insula, have been implicated in anxiety regulation and social support processing, the medial prefrontal cortex (mPFC) emerges as a particularly intriguing structure due to its central role in emotional regulation and social processing.
Here, we hypothesize that the mPFC serves as a potential neural substrate mediating the relationship between anxiety and perceived social support. To support our hypothesis, we conducted a literature search in the PubMed database using a systematic Boolean search strategy. In total, 43 articles met our inclusion criteria. The reviewed studies suggest that the mPFC may play an essential role in regulating the effect of perceived social support on anxiety levels. The evidence indicates that individuals with higher levels of perceived social support may exhibit enhanced regulatory control over anxiety-related processes, with the mPFC mediating this effect.
Understanding the neural mechanisms that underpin the relationship between anxiety and social support is crucial for devising targeted interventions. Further investigation into mPFC's role as a candidate structure in this domain could provide invaluable insights and aid in the development of new therapeutic strategies for the management of anxiety.
... Additionally, approach motivations like behavioral aggression may be associated with greater left frontal activity, [71][72][73][74] and left VLPFC anodal stimulation has been shown to increase aggression in healthy subjects. 75 Alternatively, prefrontal areas other than VLPFC, such as DLPFC, could be more involved in modulating cognitive control and impulsivity after ostracism. 31,76 Previous studies stimulating right DLPFC in BPD patients, indeed, have shown decreased anger, aggression, and impulsivity, suggesting it may promote functional control strategies. ...
Aims
Borderline personality disorder (BPD) patients show negative emotional reactions to both excluding and including social scenarios, with levels normalizing only during extreme inclusion. Prior research among healthy individuals highlights the right ventrolateral prefrontal cortex (rVLPFC) role in regulating emotional responses to social exclusion, since transcranial direct current stimulation (tDCS) of rVLPFC decreases rejection‐related emotions following social exclusion. This pilot study investigated whether, in BPD patients, tDCS over the rVLPFC reduces rejection‐related emotions not only after social exclusion but also after fair social inclusion.
Methods
Forty BPD patients randomly received either real or sham tDCS on rVLPFC before participating in the Cyberball paradigm, which involved phases of inclusion, exclusion, and over‐inclusion. Participants self‐reported their level of rejection‐related emotions following each phase.
Results
Transcranial direct current stimulation reduced rejection‐related emotions during both social exclusion and fair inclusion, but not during over‐inclusion. Specifically, those in the Real tDCS group exhibited comparable emotional responses to fair and over‐including scenarios, unlike those in the Sham group who experienced heightened rejection‐related emotions during fair inclusion compared to over‐inclusion.
Conclusions
Transcranial direct current stimulation over the rVLPFC reduces BPD patients' tendency to feel rejected both in fairly including and excluding scenarios. These findings confirm the rVLPFC involvement in emotional regulation and highlight a therapeutic potential for tDCS in moderating BPD's typical heightened rejection‐related emotional responses to fairly including scenarios. This study supports the application of tDCS in BPD treatment, providing new insights into neuromodulatory interventions that can aid BPD patients to better regulate their emotions during varying social scenarios.
... Prefrontal cortex Top-down control over subcortical regions involved in processing threatening stimuli. [72] Orbitofrontal cortex Part of the top-down circuitry that mediates reactive aggression. ...
The belief that people suffering from psychiatric disorders are more violent, in particular psychotic patients that do not have insight into their illness, is very common in the general population. Therefore, this review aimed to present a more accurate depiction of the link between lack of insight and violent behavior, by evaluating the existing scientific literature on the topic. For this purpose, a literature search on PubMed, Embase, and Google Scholar was conducted, selecting the relevant papers published during a 20-year period (2004–2024). The paper defined insight as a multi-dimensional concept and discussed its classification, explanatory models, and clinical implications, followed by a presentation of several insight-measuring scales. The meaning of violent behavior, its prevalence, underlying mechanisms, and different measuring scales were discussed, followed by the confounding factors that influence the relationship between insight and violent behavior, treatment options for violence in forensic psychiatry settings, and methods to improve medication adherence. Contrasting results were observed regarding the impact of each factor on leading to violent acts, which suggested that the relationship between insight and violence is more complex than previously thought. In conclusion, increased attention must be paid to the investigated dimensions of both the concepts and the confounding factors, with further research required on this topic.
... There are reasons to further investigate this topic, provided that (a) sex differences have been reported in a wide variety of animal models of negative emotions (including operant reward downshift tasks; Weinstein, 1978), with the direction of the differences depending on the particular features of the behavioral test (e.g. Gray, 1987;Johnston and File, 1991); and (b) inconsistent differences between men and women have been shown throughout the lifespan in situations involving unexpected reward loss, reward barrier, social rejection, and frustration-induced aggression (Devi, 1967;Gentry, 1970;Feiring and Lewis, 1979;Maciejewski et al., 2001;Stroud et al., 2002;Verona and Curtin, 2006;Eriksson and Simpson, 2010;Gallucci et al., 2020;Dhingra et al., 2021;Srivastava, 2023). ...
Increased voluntary consumption of alcohol has been demonstrated in male rats exposed to frustrative reward downshift (the emotional self-medication effect). Access to a wheel for voluntary running abolished this effect in male rats, suggesting an attenuating effect of physical exercise on the negative affect induced by reward downshift and its consequences on drug intake. The present study analyzed this effect in female rats. Sixty-four food-deprived female Wistar rats received 32% sucrose [4% (Experiment 1) or 2% (Experiment 2) in controls] during 10, 5-min preshift sessions followed by 4% (Experiment 1) or 2% (Experiment 2) sucrose during 5 postshift sessions. Immediately after each consummatory session, animals were exposed to a 2-h, two-bottle preference test involving 32% alcohol vs. water. Half of the animals also had access to a running wheel during the preference test. The results showed (a) lower sucrose consumption in the downshifted groups (32–4% and 32–2%) compared to the unshifted controls (4–4% and 2–2%, respectively); (b) higher alcohol preference in downshifted groups without access to a wheel compared with downshifted groups with access to the wheel (Experiments 1 and 2); and (c) increased alcohol intake (g/kg) after experiencing reward downshift in animals without access to the wheel (Experiment 1). Voluntary wheel running thus reduced alcohol intake in female rats experiencing reward downshift. These findings are comparable to previous results reported in male rats and support the usefulness of physical exercise to prevent alcohol self-medication induced by frustrative nonreward.
... A study demonstrated that increased RA levels are associated with reduced middle frontal cortex volumes [28]. Gallucci found that experimentally induced frustration increased RA following transcranial direct current stimulation (tDCS) of the left ventrolateral prefrontal cortex [29]. Participants who received anodal tDCS on the right dorsolateral prefrontal cortex experienced reduced PA [30]. ...
Objectives: This study explores whether sex differences in reactive aggression (RA) and proactive aggression (PA) are attributable to sex, gender role orientation, or their interaction and explores the neuroanatomical characteristics of these sex differences. Methods: In a sample of 108 males and 126 females, we examined the sex-by-gender role orientation interaction on RA, PA, and brain gray matter volume (GMV). Then, we explored the relationship between aggression and regional GMV. Results: When the effects of sex and gender role orientation on aggression were disentangled, there were no sex differences in RA, regardless of gender role orientation. However, sex differences (male > female) in PA were observed within the masculine group but not within the feminine group. Brain imaging results revealed sex differences (male > female) on the right inferior frontal gyrus GMV, a region involved in cognitive control, within the masculine group. Moreover, a negative association between PA and the right inferior frontal gyrus GMV was observed in masculine females rather than masculine males. Conclusions: These findings indicate that gender role orientation has a more significant effect on aggression than sex, particularly with regard to PA, and hint that the goal of cognitive control involved in displaying PA differs in masculine males and masculine females.
... On the other hand, females may suppress this aggressive impulse, resulting in fewer instances of cyberbullying. Previous research has found that males exhibit more aggressive behaviors than females when faced with frustrations (Gallucci et al., 2020). From a biological perspective, violent behaviors have been linked to the male hormone testosterone. ...
Previous studies have found that adolescent cyberbullying victimization is associated with cyberbullying perpetration and have explored the potential mediating mechanisms between the two. Although some valuable research has been accumulated, further exploration is needed on the underlying mechanisms of why cyber victims are transformed into cyberbullying perpetrators. Based on the General Aggression Model of Cyberbullying and the Social Role Theory, this study examined the mediating role of psychological entitlement and the moderating role of gender on the relationship between cyberbullying victimization and cyberbullying perpetration. A questionnaire survey was conducted on 836 adolescents, utilizing the cyberbullying victimization scale, cyberbullying perpetration scale, and psychological entitlement questionnaire. The results found that (a) cyberbullying victimization, psychological entitlement, and cyberbullying perpetration were significantly and positively correlated with each other; (b) after controlling for gender and age, cyberbullying victimization significantly and positively predicted cyberbullying perpetration and psychological entitlement mediated the relationship between cyberbullying victimization and cyberbullying perpetration; (c) Gender moderates the relationship between cyberbullying victimization and cyberbullying perpetration. Specifically, compared with the girls, cyberbullying victimization had a greater effect on cyberbullying perpetration among boys. The results of this study suggest that cyberbullying victims consider that they have more entitlement to bully others online. These findings support the General Aggression Model of Cyberbullying and provide new insights for the prevention and intervention of cyberbullying perpetration.
... Literatürde engellenmenin saldırganlığı artırdığı yönünde de bulgular bulunmaktadır. (17)(18)(19)(20) Ülkemizde de çocukların olumlu davranış geliştirmesi amacıyla ceza yönteminin kullanılması yaygın olarak görüldüğü düşünüldüğünde, araştırmadan elde edilen bu bulgunun da, cezaların kullanılmasının çocuklarda saldırgan davranışı engellemediği, aksine ceza verildiği durumlarda saldırganlık davranışlarını da artırdığını göstermektedir. ...
Amaç: Bu araştırma 10-12 yaşlarındaki öğrencilerin saldırganlık eğilimleri ve etkileyen ailesel faktörlerin belirlenmesi amacıyla tanımlayıcı olarak yapılmıştır. Yöntem: Araştırmaya, Ankara’daki bir ilköğretim okulundaki 10-12 yaşlarındaki öğrencilerin tamamı (90 öğrenci) dahil edilmiştir. Veriler “Kişisel Bilgi Formu” ve beş alt ölçeği olan “Saldırganlık Ölçeği” ile toplanmıştır. Bulgular: Öğrencilerin saldırganlık alt ölçekleri puan ortalamaları “Saldırganlık Bunalımı” için 44.52±8.94, “Yansıtılmış Saldırganlık" için 43.07±8.12, “Kendine Yönelik Saldırganlık” için 14.29±4.12, “Prososyal Saldırganlık” için 28.50±5.18, “Antisosyal Saldırganlık" için 23.91±6.45’dir. Öğrencilerin saldırganlık alt ölçeklerinin puan ortalamaları ile ailede çocuğun kararlara katılımı, anne ve babanın çocuğa kızdıklarında verdikleri tepki, anne ve babanın birbirlerine kızdıklarında gösterdikleri tepki, anne ve babanın çocuğa ceza vermesi ve çocuğa karşı tutumu arasında istatistiksel anlamlılıkta bir fark olduğu saptanmıştır. Sonuç: Araştırma sonucuna göre anne, baba ve çocuk iletişimini kapsayan tutum ve davranışların saldırganlıkta önemli bir rol oynadığı görülmektedir. Öğrenci ve ailelerine saldırganlığı önlemeye yönelik tutum ve yaklaşımlar konusunda danışmanlık hizmetlerinin planlanması önerilmiştir.
... It should be noted that the results might not be representative for males as 80% of the study sample consisted of female participants. For the cerebrum, several studies have demonstrated sex differences in the effects of tDCS on cortical excitability, electric field modeling and task-related functions [63][64][65][66][67][68]. For example, these differences have been suggested to involve sex-dependent variability in hormones, brain anatomy and neurophysiology [63,[68][69][70][71][72]. ...
It has recently been theorized that the frontal asymmetry of approach- and avoidance-related motivation is mirrored in the posterolateral cerebellum. Accordingly, left-to-right dominant cerebellar activity is associated with avoidance-related motivation, whereas right-to-left dominant cerebellar activity is associated with approach-related motivation. The aim of this study was to examine the cerebellar asymmetry of motivational direction in approach-related behavior in the context of aggression. In this randomized double-blind sham-controlled crossover study, thirty healthy right-handed adult volunteers received 2 mA active or sham left cathodal-right anodal transcranial direct current stimulation (tDCS) to the cerebellum on two separate occasions while engaging in the Point Subtraction Aggression Paradigm (PSAP) task to measure aggressive behavior. Self-reported state anger was assessed before, halfway and immediately after the task, and heart rate and heart rate variability (HRV) were measured during the task. No main effects of tDCS on aggressive behavior, heart rate and HRV were found. Higher state anger before and during the PSAP task was associated with increased aggressive behavior in the active compared to sham tDCS condition. Aggressive behavior was positively correlated with heart rate during active tDCS, while an inverse association was observed during sham tDCS. Results provide support for the cerebellar asymmetry of motivational direction in approach-related behavior and illustrate the importance of affective state-dependency in tDCS-related effects.
Supplementary Information
The online version contains supplementary material available at 10.1007/s12311-023-01644-z.
... Intentions to commit aggression have also been shown to be reduced following stimulation . However, there are also findings of increased frustration and anger-induced aggression following anodal tDCS (Gallucci et al., 2020;Hortensius et al., 2011), as well as null findings on the effect of prefrontal tDCS on aggressive behavior (Dambacher et al., 2015a;Hortensius et al., 2011;Ling et al., 2020). ...
... Intentions to commit aggression have also been shown to be reduced following stimulation . However, there are also findings of increased frustration and anger-induced aggression following anodal tDCS (Gallucci et al., 2020;Hortensius et al., 2011), as well as null findings on the effect of prefrontal tDCS on aggressive behavior (Dambacher et al., 2015a;Hortensius et al., 2011;Ling et al., 2020). ...
... For example, one study found that increasing activity in the right prefrontal cortex reduced proactive aggression in males, but not in females [28]. In another study, although males exhibited greater aggressive behavior than females after sham stimulation, the difference in aggression levels between males and females was significantly reduced after anodal tDCS over the right and left vlPFC [29]. These results showing that females who received prefrontal cortical stimulation were as aggressive as males suggest that there may be differences in the way males and females respond to the effects of tDCS on aggressive behavior. ...
Findings from brain imaging studies investigating the neural underpinnings of antisocial behavior have implicated the prefrontal cortex in the regulation of aggressive reactions. However, relatively few studies have examined the role of the prefrontal cortex on aggression in an experimental way. This study examines whether upregulating the prefrontal cortex using repeated transcranial direct current stimulation (tDCS) reduces aggressive behavior. In a double-blind, parallel-group, randomized controlled trial, 88 healthy adults (42 males, 46 females) were assigned to one session of anodal tDCS over the ventromedial prefrontal cortex (n = 47) or sham stimulation (n = 41) per day for three consecutive days and assessed using a behavioral measure of aggression. Levels of aggressive responses post-intervention did not significantly differ between the active and sham stimulation groups. However, a significant interaction effect between the stimulation group and gender was observed, whereby males, but not females, exhibited reduced aggression after prefrontal stimulation. To the authors’ knowledge, this is the first study to examine the effect of multi-session prefrontal tDCS on aggressive behavior in healthy adults. Results highlight that there are differences in responsivity to tDCS in modifying aggressive behavior.
... 25 The relationship between the prefrontal cortex and the risk of physical violence revealed that aggression can be modulated by stimulating the ventral lateral prefrontal cortex. 26 In addition, several studies in recent years have reported alterations in the functional connections between the anterior cingulate gyrus and the amygdala and caudate nucleus during the first manic episode. 27,28 Patients with multiple episodes of BD exhibit hypoactivation in areas, such as the bilateral ventral lateral prefrontal cortices and amygdala networks in the prefrontal-striatal-amygdala circuit. ...
Purpose
Identifying patients with bipolar disorder (BD) in manic states (BD-M) who are at a high risk of physical violence is a matter of clinical concern. This retrospective institution-based study aimed to identify simple, rapid, and inexpensive clinical markers of physical violence in patients with BD-M.
Patients and Methods
The anonymized sociodemographic variables (sex, age, years of education, marital status) and clinical ones (weight, height, body mass index, blood pressure, the score of BRMS, number of BD episodes, psychotic symptoms, history of violence, biochemical parameters, and blood routine parameters) of 316 BD-M participants were collected, and the risk of physical violence was identified using the Brøset Violence Checklist (BVC). Difference tests, correlation analyses, and multivariate linear regression analysis were performed to identify clinical markers for the risk of physical violence.
Results
The participants were categorized into groups at low (49, 15.51%), medium (129, 40.82%), and high (138, 43.67%) risk of physical violence. The number of BD episodes, serum uric acid (UA), free thyroxine (FT4) levels, history of violence, and monocyte-to-lymphocyte ratio (MLR) differed significantly between groups (all P<0.05). The number of BD episodes (r=0.152), FT3 (r=0.131) and FT4 (r=0.132) levels, history of violence (r=0.206), and MLR (r=−0.132) were significantly correlated with the risk of physical violence (all P<0.05). The existence of history of violence, number of BD episodes, UA, FT4, and MLR were identified as clinical markers of the risk of physical violence in patients with BD-M (all P<0.05).
Conclusion
These identified markers are readily available at initial presentation and may help in the timely assessment and treatment of patients with BD-M.
... This asymmetry has also been confirmed when considering aggressive behaviours. For example, the stimulation of the left ventrolateral PFC increases aggression [31], while the stimulation of the right dorsolateral PFC can reduce proactive but not reactive aggression [32]. ...
Anger can be broken down into different elements: a transitory state (state anger), a stable personality feature (trait anger), a tendency to express it (anger-out), or to suppress it (anger-in), and the ability to regulate it (anger control). These elements are characterized by individual differences that vary across a continuum. Among them, the abilities to express and suppress anger are of particular relevance as they determine outcomes and enable successful anger management in daily situations. The aim of this study was to demonstrate that anger suppression and expression can be decoded by patterns of grey matter of specific well-known brain networks. To this aim, a supervised machine learning technique, known as Kernel Ridge Regression, was used to predict anger expression and suppression scores of 212 healthy subjects from the grey matter concentration. Results show that individual differences in anger suppression were predicted by two grey matter patterns associated with the Default-Mode Network and the Salience Network. Additionally, individual differences in anger expression were predicted by a circuit mainly involving subcortical and fronto-temporal regions when considering whole brain grey matter features. These results expand previous findings regarding the neural bases of anger by showing that individual differences in specific anger-related components can be predicted by the grey matter features of specific networks.
... It is also suggested that social anxiety disorder (SAD) may be due to dysfunction of VLPFC. [33] Reduced gray matter volume in the right VLPFC is found related to suicidal ideation. [34] Over-activation of VLPFC is found in adolescents with a generalized anxiety disorder (GAD). ...
Prefrontal cortex (PFC) has been referred to as the personality center in the human brain ever since Phineas Gage changed into another person after suffering damage to his PFC. Among the areas of frontal lobe, subregions of this area of the cortex perform the most important cognitive functions. All subregions are found related to important executive functions such as abstract reasoning, learning, decision-making, regulation of emotions, integrating inputs from the environment and reacting to them. Prefrontal cortex subregions perform their functions by working together with other brain regions and integrating them. Impairment in any of these subregions is connected to the majority of researched psychiatric disorders, such as anxiety, depression, and suicidal ideation, because of their crucial roles in behavior and psychology. Therefore, expanding data of the PFC studies especially in humans provides a new perspective on cognition and psychiatric disorders. In this review, the human prefrontal cortex and its functions were discussed.
... This asymmetry has also been confirmed when considering aggressive behaviours. For example, the stimulation of the left ventrolateral PFC increases aggression [31], while the stimulation of the right dorsolateral PFC can reduce proactive but not reactive aggression [32]. ...
... Furthermore, anodal tDCS of rVLPFC increases pain and aggression induced by ostracism (Riva et al., 2012;Riva et al., 2015a), whereas cathodal stimulation of rVLPFC increases negative emotions induced by ostracism (Riva et al., 2015b). Recent study also showed that only anodal stimulation to left VLPFC and not right VLPFC decreased aggression after frustration (Gallucci et al., 2020). Moreover, the top-down process of regulation is being boosted when rVLPFC is stimulated with tDCS during reappraisal of negative emotions related to watching pictures of social exclusion (He et al., 2018;He et al., 2020). ...
Exclusion has multiple adverse effects on individual’s well-being. It induces anger and hostile cognitions leading to aggressive behavior. The purpose of this study was to test whether exclusion would affect recognition of anger on ambivalent faces of the excluders. We hypothesized that exclusion would elicit more anger encoding (hostility bias) than inclusion, but this effect would be mitigated by anodal tDCS of right VLPFC or left DLPFC—regions engaged in negative affect regulation. Participants (N = 96) were recognizing emotions (anger, sadness, happiness) on ambiguous faces of individuals who—as they were told—liked them or not. Results showed that exclusion induced more sadness bias. tDCS to VLPFC decreased anger and increased sadness recognition on excluders’ faces compared with includers’ faces, expressing a mixture of these two emotions. Additionally, stimulation to VLPFC and DLPFC decreased latencies for faces expressing sadness (sad-angry and happy-sad) but increased for happy-angry faces. Stimulation to VLPFC also increased reaction time to excluders faces while stimulation of DLPFC decreased reaction latency to includers faces. Results were discussed with the reference to the form of exclusion, motivational mechanism affected by disliking but also to lateralization (valence vs. arousal theory) and cortical regions engaged in encoding sadness after a threat to belonging.
... Nevertheless, evidence suggests that lesions and transcranial stimulation of FIC regions are both associated with exaggerated emotional responses (Agustín-Pavón et al., 2012;Gallucci, Riva, Lauro, & Bushman, 2020;Riva et al., 2017;Riva, Romero Lauro, DeWall, Chester, & Bushman, 2015;Shiba, Kim, Santangelo, & Roberts, 2015;Vergallito, Riva, Pisoni, & Lauro, 2018). ...
Early evidence suggests that unexpected non-reward may increase the risk for aggressive behaviors. Despite the growing interest in understanding brain functions that may be implicated in aggressive behaviors, the neural processes underlying such frustrative events remain largely unknown. Furthermore, meta-analytic results have produced discrepant results, potentially due to substantial differences in the definition of anger/aggression constructs. Therefore, coordinate-based meta-analyses on unexpected non-reward and retaliatory behaviors in healthy subjects were conducted. Conjunction analyses were further examined to discover overlapping brain activations across these meta-analytical maps. Frustrative non-reward deactivated the orbitofrontal cortex, ventral striatum and posterior cingulate cortex, whereas increased activations were observed in midcingulo-insular regions, as well as dorsomedial prefrontal cortex, amygdala, thalamus and periaqueductal gray, when using liberal threshold. Retaliation activated of midcingulo-insular regions, the dorsal caudate and the primary somatosensory cortex. Conjunction analyses revealed that both strongly activated midcingulo-insular regions. Our results underscore the role of anterior midcingulate/pre-supplementary motor area and fronto-insular cortex in both frustration and retaliatory behaviors. A neurobiological framework for understanding frustration-based impulsive aggression is provided.
... When provoked, these experiments found that anodal (i.e., inhibitory) stimulation to the self-regulation network (i.e., the right DLPFC, right vlPFC, and centralized or right vmPFC) decreased aggression (Chen, 2018;Dambacher et al. 2015a;Gilam et al., 2018;Hortensius et al., 2012;Riva et al., 2015Riva et al., , 2017. By contrast, in other studies, anodal stimulation to the left vlPFC or DLPFC increased aggressive behavior in the laboratory (Gallucci et al., 2020;Hortensius et al., 2012) and right DLPFC stimulation increased angry rumination (Kelley et al., 2013). Another found no effect of stimulation to either the left or right vlPFC on aggression during the Taylor paradigm (Dambacher et al., 2015b). ...
Violent crime elicits demand for punishment from the public, which can influence policy toward offenders. Paradoxically, harsh punishments such as incarceration often increase offending rather than deter it, which produces a cycle of violent crime and punishment. Violent offenders frequently possess risk factors that influence brain structure and function. These risk factors are genetic predisposition toward violence, adverse childhood experiences, alcohol use, and traumatic brain injury. The alteration in brain structure and function appears primarily in networks involved in threat detection (e.g., biased sensitivity to provocation), self-regulation (e.g., control over anger and aggressive urges), and social cognition (e.g., thinking about others’ motives). If there is no treatment in people with these risk factors, brain responses to anger provocation will likely increase risk for reactive aggression. As a method to circumvent the cycle of violence and punishment, this review discusses the notion of normalizing brain responses to provocation such that they resemble responses of nonviolent people. A growing body of research suggests that brain normalization can occur by using biomedical instruments such as pharmaceuticals and brain stimulation to enhance moral behavior. Normalizing brain function via moral bioenhancement should inhibit reactive aggression. If such normalization occurs, there is no violent act to punish and hence the cycle of crime and punishment is broken. Policy makers may consider investing in trials of moral bioenhancement that could support existing treatments to reduce violence and recidivism and their associated costs. © 2020 The Society for the Psychological Study of Social Issues
... In particular, the left VLPFC is involved in the assessment of emotion and conscious impulse control. So, impaired function of vlPFC can lead to [20]. And, the vlPFC is responsible for producing a negative emotional experience [37], so excessive activation of the vlPFC can produce unpleasant emotions. ...
Background:
Many studies have found that the hippocampus plays a very important role in major depressive disorder (MDD). The hippocampus can be divided into three subfields: the cornu ammonis (CA), dentate gyrus (DG) and subiculum. Each subfield of the hippocampus has a unique function and are differentially associated with the pathological mechanisms of MDD. However, no research exists to describe the resting state functional connectivity of each hippocampal subfield in MDD.
Methods:
Fifty-five patients with MDD and 25 healthy controls (HCs) matched for gender, age and years of education were obtained. A seed-based method that imposed a template on the whole brain was used to assess the resting-state functional connectivity (rsFC) of each hippocampal subfield.
Results:
Patients with MDD demonstrated increased connectivity in the left premotor cortex (PMC) and reduced connectivity in the right insula with the CA seed region. Increased connectivity was reported in the left orbitofrontal cortex (OFC) and left ventrolateral prefrontal cortex (vlPFC) with the DG seed region. The subiculum seed region revealed increased connectivity with the left premotor cortex (PMC), the right middle frontal gyrus (MFG), the left ventrolateral prefrontal cortex (vlPFC) and reduced connectivity with the right insula. ROC curves confirmed that the differences between groups were statistically significant.
Conclusion:
The results suggest that the CA, DG and subiculum have significant involvement with MDD. Specifically, the abnormal functional connectivity of the CA may be related to bias of coding and integration of information in patients with MDD. The abnormal functional connectivity of the DG may be related to the impairment of working memory in patients with MDD, and the abnormal functional connectivity of the subiculum may be related to cognitive impairment and negative emotions in patients with MDD.
In this study, using the self/other adjective judgment task, we aimed to explore how people perceive themselves in comparison to various other people, including friends, strangers, and those they dislike. Next, using representational similarity analysis, we sought to elucidate how these perceptual similarities and differences are represented in brain activity and how aggressiveness is related to these representations. Behavioral ratings show that, on average, people tend to consider themselves more like their friends than neutral strangers, and least like people they dislike. This pattern of similarity is positively correlated with neural representation in social and cognitive circuits of the brain and negatively correlated with neural representation in emotional centers that may represent emotional arousal associated with various social objects. Aggressiveness seems to predispose a person to a pattern of behavior that is the opposite of the average pattern, that is, a tendency to think of oneself as less like one's friends and more like one's enemies. This corresponds to an increase in the similarity of the behavioral representation with the representation in the emotional centers and a decrease in its similarity with the representation in the social and cognitive centers. This can be seen as evidence that in individuals prone to aggression, behavior in the social environment may depend to a greater extent on the representation of social objects in the emotional rather than social and cognitive brain circuits.
Saldırganlığın Nöroanatomisi
Here we performed a before-after ABA-design study in police cadets (N = 82) to compare the effects of unexpected (event-triggered) and expected (anticipatory) stressors on aggression. On the first day of the study, participants filled in the Buss-Perry Aggression Questionnaire (BPAQ) and the Barratt Impulsiveness Scale (BIS) and were fitted with heart rate (HR) monitors, which remained attached till the end of the study. On day 2, they were instructed to perform a police intervention in a realistic training environment. The intervention was preceded either by a warning or by a reassuring audio recording that forecasted violent or routine interventions, respectively. Both groups encountered hostile suspects at the intervention site, the behavior of which, however, did not justify the use of force e.g., aggression. The warning resulted in a gradually developing anticipatory stress as shown by HRs. Cadets exposed to the reassuring audio recording showed minimal anticipatory stress but responded to the hostile suspects by an abrupt increase in HRs, which was missing in the warned group. The magnitude of HR responses was similar in the two groups, only their temporal evolution differed. Although aggression showed some associations with BPAQ and BIS scores, the main predictors of behavior were HR changes according to a Multiple Regression analysis. The gradually developing anticipatory stress was associated with low, whereas the abrupt increase in HRs was associated with high aggression. Our findings suggest that the anticipation of a stressful event improves behavioral control whereas an unexpected stress strongly promotes aggression.
Background
Early evidence suggests that unexpected non-reward may increase the risk for aggressive behaviors. Despite the growing interest in understanding brain functions that may be implicated in aggressive behaviors, the neural processes underlying such frustrative events remain largely unknown. Furthermore, meta-analytic results have produced discrepant results, potentially due to substantial differences in the definition of anger/aggression constructs.
Methods
Therefore, we conducted a coordinate-based meta-analysis, using the activation likelihood estimation algorithm, on neuroimaging studies examining reward omission and retaliatory behaviors in healthy subjects. Conjunction analyses were further examined to discover overlapping brain activations across these meta-analytic maps.
Results
Frustrative non-reward deactivated the orbitofrontal cortex, ventral striatum and posterior cingulate cortex, whereas increased activations were observed in midcingulo-insular regions. Retaliatory behaviors recruited the left fronto-insular and anterior midcingulate cortices, the dorsal caudate and the primary somatosensory cortex. Conjunction analyses revealed that both strongly activated midcingulo-insular regions.
Conclusions
Nonetheless, our results underscore the role of anterior midcingulate/pre-supplementary motor area and fronto-insular cortex in both frustration and retaliatory behaviors. A neurobiological framework for understanding frustration-based impulsive aggression is provided.
The Tangram Help/Hurt Task (THHT) allows participants to help another participant win a prize (by assigning them easy tangrams), to hurt another participant by preventing them from winning the prize (by assigning them difficult tangrams), or to do neither (by assigning them medium tangrams) in offline or online studies. Consistent with calls for continued evidence supporting psychological measurement, we conducted a meta-analytic review of the THHT that included 52 independent studies involving 11,060 participants. THHT scores were associated with helping and hurting outcomes in theoretically predicted ways. Results showed that THHT scores were not only associated with short-term (experimental manipulations, state measures) and long-term (trait measures) helping and hurting outcomes, but also with helping and harming intentions. We discuss the strengths and limitations of the THHT relative to other laboratory measures of prosocial behavior and aggression, discuss unanswered questions about the task, and offer suggestions for the best use of the task.
Containing aggressive behavior is an ongoing challenge in modern society. Aggressiveness is a multi‐level construct that can be driven by emotions (reactive aggression) or can be “cold‐blooded” and goal‐directed (proactive). Aggressive behavior could arise because of a misjudgment of others' intentions or can follow frontal brain lesions leading to a reduction of impulse control and emotion regulation. In the last few years, interventional and basic research studies adopting Non‐Invasive Brain Stimulation (NIBS) have significantly risen. Those techniques have been used both in healthy people, to better understand the role of certain brain regions in psychological processes, and in aggressive subjects to improve their symptoms. From an overview of the literature, focusing on the paper that uses transcranial direct current stimulation (tDCS) to reduce aggressiveness, it emerges that tDCS can (i) enhance facial emotion expression recognition, (ii) improve impulses control, and (iii) affect approach/withdrawal motivation. The current work shows the strengths and weaknesses of tDCS intervention on aggressive individuals, suggesting that this instrument could be adopted on violent people, and paves the way for intervention in some applied settings such as prison.
Prosociality improves with interpersonal synchronization—the temporal coordination of movement across individuals. We tested whether the benefits of interpersonal synchronization extend to temporary circumstances of induced frustration, where negative changes in prosociality are expected as a result. Participants performed two joint tasks—synchronization versus non-synchronization. Each task was performed twice, with high versus low induced frustration. After each joint task, prosociality was measured both with explicit tests, in which participants were aware of the test goal, and implicit ones, where they were less aware. Frustration levels per task were also reported. Results showed that increase in frustration led to decrease in implicit prosociality after the non-synchronization task, but not after synchronization, suggesting that interpersonal synchronization attenuates the antisocial outcomes of frustration. In addition, our study highlights the advantages of implicit measures of prosociality, among which the test we created (Interpersonal Trust Test) may stand as a useful resource in future experimental research.
Introduction
The observed variability in the effects of transcranial direct current stimulation (tDCS) is influenced by the amount of current reaching the targeted region-of-interest (ROI). Age and sex might affect current density at target ROI due to their impact on cortical anatomy. The present tDCS simulation study investigates the effects of cortical anatomical parameters (volumes, dimension, and torque) on simulated tDCS current density in healthy young, middle-aged, and older males and females.
Methodology
Individualized head models from 240 subjects (120 males, 18–87 years of age) were used to identify the estimated current density (2 mA current intensity, 25 cm² electrode) from two simulated tDCS montages (CP5_CZ and F3_FP2) targeting the inferior parietal lobule (IPL) and middle frontal gyrus (MFG), respectively. Cortical parameters including segmented brain volumes (cerebrospinal fluid [CSF], grey and white matter), cerebral-dimensions (length/width & length/height) and brain-torque (front and back shift, petalia, and bending) were measured using the magnetic resonance images (MRIs) from each subject. The present study estimated sex differences in current density at these target ROIs mediated by these cortical parameters within each age group.
Results
For both tDCS montages, females in the older age group received higher current density than their male counterparts at the target ROIs. No sex differences were observed in the middle-aged group. Males in the younger age group had a higher current density than females, only for the parietal montage. Across all age groups, CSF, and grey matter volumes significantly predicted the current intensity estimated at the target sites. In the older age group only, brain-torque was a significant mediator of the sex difference.
Conclusions
Our findings demonstrate the presence of sex differences in the simulated tDCS current density, however this pattern differed across age groups and stimulation locations. Future studies should consider influence of age and sex on individual cortical anatomy and tailor tDCS stimulation parameters accordingly.
Background: Approximately half of all people with alcohol use disorder (AUD) relapse into alcohol reuse in the next few weeks after a withdrawal treatment. Brain stimulation and cognitive training represent recent forms of complementary interventions in the context of AUD.
Objective: To evaluate the clinical efficacy of five sessions of 2 mA bilateral transcranial direct current stimulation (tDCS) for 20 minutes over the dorsolateral prefrontal cortex (DLPFC) (left cathodal/right anodal) combined with alcohol cue inhibitory control training (ICT) as part of rehabilitation.
Methods: A randomized clinical trial with patients (n=125) with severe AUD at a withdrawal treatment unit. Each patient was randomly assigned to one of four conditions, in a 2 [verum vs. sham tDCS] x 2 [alcohol cue vs. neutral ICT] factorial design. The main outcome of treatment was the abstinence rate after two weeks or more (up to one year).
Results: Verum tDCS improved the abstinence rate at the 2-week follow-up compared to the sham condition, independently of the training condition (79.7% [95% CI = 69.8-89.6] vs. 60.7% [95% CI = 48.3-73.1]; p = 0.02). A priori contrasts analyses revealed higher abstinence rates for the verum tDCS associated with alcohol cue ICT (86.1% [31/36; 95% CI = 74.6-97.6]) than for the other three conditions (64% [57/89; 95% CI = 54-74]). These positive clinical effects on abstinence did not persist beyond two weeks after the intervention.
Conclusions: AUD patients who received tDCS applied to DLPFC showed a significantly higher abstinence rate during the weeks following rehabilitation. When combined with alcohol specific ICT, brain stimulation may provide better clinical outcomes.
Irritability (i.e., a proneness to anger that is often accompanied by behavioral outbursts) is increasingly recognized as a clinically significant trait in adults, yet studies into its mechanisms and whether they differ from those observed in pediatric samples is largely unknown. Although face emotion identification deficits are associated with increased irritability in children, mixed findings exist in the two studies of trait irritability in adults. In an online sample of adults (N = 209, 18–62 years; M = 30.15), we sought to address some of the methodological limitations in prior studies to test whether irritability is associated with difficulties recognizing emotional expressions following frustration. Trait irritability was not associated with impaired face emotion identification, even after a frustration manipulation. This suggests that irritability-related mechanisms in adults may differ from those observed in pediatric samples or may be limited to adults with clinically significant irritability.
Background
Anodal transcranial direct current stimulation (tDCS) of the somatosensory cortex causes cerebral hyperexcitability and a significant enhancement in pain thresholds and tactile spatial acuity. Sensory gating is a brain mechanism to suppress irrelevant incoming inputs, which is elicited by presenting pairs of identical stimuli (S1 and S2) within short time intervals between stimuli (e.g., 500 ms).
Objectives/Hypothesis
The present study addressed the question of whether tDCS could modulate the brain correlates of this inhibitory mechanism.
Methods
Forty-one healthy individuals aged 18–26 years participated in the study and were randomly assigned to tDCS (n = 21) or SHAM (n = 20). Somatosensory evoked potentials (SEP) elicited by S1 and S2 pneumatic stimuli (duration of 100 ms, ISI 550 ± 50 ms) and applied to the index finger of the dominant hand were recorded before and after tDCS.
Results
Before the intervention, the second tactile stimuli significantly attenuated the amplitudes of P50, N100, and the late positive complex (LPC, mean amplitude in the time window 150–350) compared to the first stimuli. This confirmed that sensory gating is a widespread brain inhibitory mechanism that can affect early- and middle-latency components of SEPs. Furthermore, our data revealed that this response attenuation or sensory gating (computed as S1 minus S2) was improved after tDCS for LPC, while no changes were found in participants who received SHAM.
Conclusion
All these findings suggested that anodal tDCS might modulate brain excitability leading to an enhancement of inhibitory mechanisms elicited in response to repetitive somatosensory stimuli during late stages of information processing.
Glucocorticoids are believed to be crucial for understanding human aggression, psychopathologies, and crime because they can bridge adverse environmental events and the brain mechanisms of aggressive behavior, both acutely – i.e., while events unfold – and on the long run, by contributing to the epigenetic signature of toxic stressors over the lifetime. Yet, the role of glucocorticoids in human aggression is debated. There is one association that raises relatively little doubts; this is the one that links acute elevations in glucocorticoid secretion to aggressive responses, which indirectly supports the frustration–aggression hypothesis, one of the most popular psychological theories. Beyond its utility in psychology, this theory might also explain certain psychopathologies and emotional crime. The association of aggression with low glucocorticoid production by contrast is more disputed. Although demonstrated by many studies, the question remains open because the opposite association – high glucocorticoids–high aggression – is a similarly recurrent finding. It was suggested that contradictions may be solved by an approach sensitive to both the type of aggression and the psychopathology underlying aggression on one side and the glucocorticoid measures employed to study the phenomenon on the other. This chapter – already armed with the biological information presented in the previous one – aims at disentangling the intricate web of connections along this concept. The ultimate aim is to understand the acute and long-term alterations in glucocorticoid secretion in response to various types of stressors and the impact of the resulting glucocorticoid state on normal and abnormal human aggression. The neural consequences of altered glucocorticoid productions will also be addressed but briefly, because this will be dealt with in subsequent chapters.
Background
Empathy can be seen as an individual factor decreasing the probability of violent, criminal behavior, whereas a lack of empathy is seen as an increasing factor to antisocial behavior. Antisocial behavior, especially aggression and impulsive behavior, is associated with dysfunctions in the prefrontal cortex. There has been a growing interest in using Transcranial Direct Current Stimulation (tDCS) as an intervention to modulate brain regions of interest and increasing activity in damaged brain areas. This paper reviews the evidence about using tDCS as a potential intervention to increase empathic abilities and decrease antisocial behavior in violent offenders.
Objective/methods
This literature review is conducted to examine what is currently known about how tDCS may modulate empathic abilities and aggressive behavior. Articles in which tDCS was used to modulate empathic abilities and/or modulate violent behavior were selected. Brain areas of interest were the Ventromedial Prefrontal Cortex and the Dorsolateral Prefrontal Cortex.
Results/conclusions
Literature collected so far support the application of tDCS as a potential tool to increase empathic abilities and reduce violence in forensic patients, especially when targeting the vmPFC. Further research on the vast parameter space of tCS (e.g. stimulation intensity, electrode location, polarity) is needed to consolidate tDCS as a tool in forensic science.
Dispositional tendencies toward appetitive motivation have been hypothesized to be related to the development of psychopathology. Moreover, decreased left-frontal cortical activity has been reported in depression and has been related to low-trait positive affect and high-trait negative affect. The present study tested the hypothesis that relatively greater left- than right-frontal cortical activity would be related to heightened approach-related dispositional tendencies. Resting frontal cortical asymmetrical activity, as measured by electroencephalographic activity in the alpha band, was examined in relation to the motivational response tendencies of a behavioral activation system (BAS) and a behavioral inhibition system (BIS), as measured by C. S. Carver and T. L. White's (1994) BIS–BAS self-report questionnaire. Results supported the hypothesis.
In this article, we meta-analytically examine experimental studies to assess the moderating effect of provocation on gender differences in aggression. Convergent evidence shows that, whereas unprovoked men are more aggressive than women, provocation markedly attenuates this gender difference. Gender differences in appraisals of provocation intensity and fear of danger from retaliation (but not negative affect) partially mediate the attenuating effect of provocation. However, they do not entirely account for its manipulated effect. Type of provocation and other contextual variables also affect the magnitude of gender differences in aggression. The results support a social role analysis of gender differences in aggression and counter A. H. Eagly and V. Steffen's (1986) meta-analytic inability to confirm an attenuating effect of provocation on gender differences in aggression.
Anger is associated with various responses. Research on the neuroscience of anger has revealed that greater left than right frontal cortical activity is associated with angry approach-oriented responses, such as aggression, whereas greater right than left frontal cortical activity is associated with inhibited angry responses mixed with anxiety. In the current research, we extended these past studies by manipulating asymmetric frontal cortical activity using transcranial direct current stimulation and assessing its influence on ruminative responses to an interpersonal insult. Results revealed that self-reported rumination was greatest for participants who received a manipulated increase in relative right frontal cortical activity compared with those who received either a manipulated increase in relative left frontal cortical activity or sham stimulation. Taken together with past findings, the current results suggest that anger associated with greater relative left frontal cortical activity predicts approach-oriented aggressive action, whereas anger associated with greater relative right frontal cortical activity predicts inhibited rumination.
Increasing evidence suggests that the right ventrolateral prefrontal cortex (rVLPFC) plays a critical role in the emotion regulation, in particular concerning negative feelings. In the present research, we applied anodal tDCS over the rVLPFC with a twofold purpose. First, we aimed at exploring the feasibility of modulating the subjective experience of emotions through tDCS in healthy participants. Second, we wanted to assess which specific emotion can be regulated (and which cannot) with this brain stimulation approach. We designed a double-blind, between-subjects, sham-controlled study in which 96 participants watched short video clips eliciting different emotions during anodal or sham tDCS over the rVLPFC. Emotional reactions to each video clip were assessed with self-report scales measuring eight basic emotions. Results showed that, in contrast to the sham condition, tDCS over the rVLPFC reduced the perceived extent of specific negative emotions, namely, fear, anxiety, and sadness, compared to other negative or positive feelings. Overall, these results support the role of rVLPFC in regulating negative emotions, mostly associated with the prevention of dangerous situations (i.e., fear, anxiety, and sadness).
This chapter describes why and how neuroscience methods can be useful for self-control theory and research. The author contrasts two models of self-control, the opposition and valuation model, with an emphasis on how each characterizes the mechanisms self-control. Next, the author reviews recent neuroscience relevant to each model derived from functional magnetic resonance imaging studies. The author closes by offering an integrated account of how self- control operates at a neurocognitive level, and suggesting ways that self-control might be improved in light of the neurally-informed model.
Increasing evidence shows that anodal transcranial direct current stimulation (tDCS) enhances cognitive performance in healthy and clinical population. Such facilitation is supposed to be linked to plastic changes at relevant cortical sites. However, direct electrophysiological evidence for this causal relationship is still missing. Here, we show that cognitive enhancement occurring in healthy human subjects during anodal tDCS is affected by ongoing brain activity, increasing cortical excitability of task-related brain networks only, as directly measured by Transcranial Magnetic Stimulation combined with electroencephalography (TMS-EEG). Specifically, TMS-EEG recordings were performed before and after anodal tDCS coupled with a verbal fluency task. To control for effects of tDCS protocol and TMS target location, 3 conditions were assessed: anodal/sham tDCS with TMS over left premotor cortex, anodal tDCS with TMS over left posterior parietal cortex. Modulation of cortical excitability occurred only at left Brodmann's areas 6, 44, and 45, a key network for language production, after anodal tDCS and TMS over the premotor cortex, and was positively correlated to the degree of cognitive enhancement. Our results suggest that anodal tDCS specifically affects task-related functional networks active while delivering stimulation, and this boost of specific cortical circuits is correlated to the observed cognitive enhancement.
Gender differences in social cognition are a long discussed issue, in particular those concerning Theory of Mind (ToM), i.e., the ability to explain and predict other people’s mental states. The aim of this randomized, double-blind, placebo-controlled study was to test the hypothesis that anodal tDCS over the medial prefrontal cortex (mPFC) selectively enhances cognitive ToM performance in females. In the first experiment we administered to sixteen females and sixteen males a cognitive ToM task during anodal or placebo tDCS over the mPFC. In the second experiment further sixteen females completed the task receiving anodal or placebo tDCS over the vertex. The results showed that anodal tDCS over the mPFC enhances ToM in females but not in males, an effect indicated by enhanced ToM in females that received anodal tDCS over the mPFC compared with females that received tDCS over the vertex. These findings are relevant for three reasons. First, we found evidence of gender-related differences in cognitive ToM, extending previous findings concerning affective ToM. Second, these differences emerge with anodal stimulation of the mPFC, confirming the crucial role of this area in cognitive ToM. Third, we show that taking into account gender-related differences is mandatory for the investigation of ToM.
Research has shown that exposure to violent media increases aggression. However, the neural underpinnings of violent-media-related aggression are poorly understood. Additionally, few experiments have tested hypotheses concerning how to reduce violent-media-related aggression. In this experiment, we focused on a brain area involved in the regulation of aggressive impulses—the right ventrolateral prefrontal cortex (rVLPFC). We tested the hypothesis that brain polarization through anodal transcranial direct current stimulation (tDCS) over rVLPFC reduces aggression related to violent video games. Participants (N = 79) were randomly assigned to play a violent or a nonviolent video game while receiving anodal or sham stimulation. Afterward, participants aggressed against an ostensible partner using the Taylor aggression paradigm (Taylor Journal of Personality, 35, 297–310, 1967), which measures both unprovoked and provoked aggression. Among those who received sham stimulation, unprovoked aggression was significantly higher for violent-game players than for nonviolent-game players. Among those who received anodal stimulation, unprovoked aggression did not differ for violent- and nonviolent-game players. Thus, anodal stimulation reduced unprovoked aggression in violent-game players. No significant effects were found for provoked aggression, suggesting tit-for-tat responding. This experiment sheds light on one possible neural underpinning of violent-media-related aggression—the rVLPFC, a brain area involved in regulating negative feelings and aggressive impulses.
Hostile men have reliably displayed an exaggerated sympathetic stress response across multiple experimental settings, with cardiovascular reactivity for blood pressure and heart rate concurrent with lateralized right frontal lobe stress (Trajanoski et al., in Diabetes Care 19(12):1412-1415, 1996; see Heilman et al., in J Neurol Neurosurg Psychiatry 38(1):69-72, 1975). The current experiment examined frontal lobe regulatory control of glucose in high and low hostile men with concurrent left frontal lobe (Control Oral Word Association Test [verbal]) or right frontal lobe (Ruff Figural Fluency Test [nonverbal]) stress. A significant interaction was found for Group × Condition, F (1,22) = 4.16, p ≤ .05 with glucose levels (mg/dl) of high hostile men significantly elevated as a function of the right frontal stressor (M = 101.37, SD = 13.75) when compared to the verbal stressor (M = 95.79, SD = 11.20). Glucose levels in the low hostile group remained stable for both types of stress. High hostile men made significantly more errors on the right frontal but not the left frontal stressor (M = 17.18, SD = 19.88) when compared to the low hostile men (M = 5.81, SD = 4.33). These findings support our existing frontal capacity model of hostility (Iribarren et al., in J Am Med Assoc 17(19):2546-2551, 2000; McCrimmon et al., in Physiol Behav 67(1):35-39, 1999; Brunner et al., in Diabetes Care 21(4):585-590, 1998), extending the role of the right frontal lobe to regulatory control over glucose mobilization.
Crowdsourcing platforms provide an affordable approach for recruiting large and diverse samples in a short time. Past research has shown that researchers can obtain reliable data from these sources, at least in domains of research that are not affectively involving. The goal of the present study was to test if crowdsourcing platforms can also be used to conduct experiments that incorporate the induction of aversive affective states. First, a laboratory experiment with German university students was conducted in which a frustrating task induced anger and aggressive behavior. This experiment was then replicated online using five crowdsourcing samples. The results suggest that participants in the online samples reacted very similarly to the anger manipulation as participants in the laboratory experiments. However, effect sizes were smaller in crowdsourcing samples with non-German participants while a crowdsourcing sample with exclusively German participants yielded virtually the same effect size as in the laboratory.
There has been an explosion of research using transcranial direct current stimulation (tDCS) for investigating and modulating human cognitive and motor function in healthy populations. It has also been used in many studies seeking to improve deficits in disease populations. With the slew of studies reporting " promising results " for everything from motor recovery after stroke to boosting memory function, one could be easily seduced by the idea of tDCS being the next panacea for all neurological ills. However, huge variability exists in the reported effects of tDCS, with great variability in the effect sizes and even contradictory results reported. In this review, we consider the interindividual factors that may contribute to this variability. In particular, we discuss the importance of baseline neuronal state and features, anatomy, age and the inherent variability in the injured brain. We additionally consider how interindividual variability affects the results of motor-evoked potential (MEP) testing with transcranial magnetic stimulation (TMS), which, in turn, can lead to apparent variability in response to tDCS in motor studies.
A vast body of research showed that social exclusion can trigger aggression. However, the neural mechanisms involved in regulating aggressive responses to social exclusion are still largely unknown. Transcranical direct current stimulation (tDCS) modulates the excitability of a target region. Building on studies suggesting that activity in the right ventrolateral prefrontal cortex (rVLPFC) might aid the regulation or inhibition of social exclusion-related distress, we hypothesized that non-invasive brain polarization through tDCS over the rVLPFC would reduce behavioral aggression following social exclusion. Participants were socially excluded or included while they received tDCS or sham stimulation to the rVLPFC. Next, they received an opportunity to aggress. Excluded participants demonstrated cognitive awareness of their inclusionary status, yet tDCS (but not sham stimulation) reduced their behavioral aggression. Excluded participants who received tDCS stimulation were no more aggressive than included participants. tDCS stimulation did not influence socially included participants' aggression. Our findings provide the first causal test for the role of rVLPFC in modulating aggressive responses to social exclusion. Our findings suggest that modulating activity in a brain area (i.e., the rVLPFC) implicated in self-control and emotion regulation can break the link between social exclusion and aggression.
Antisocial behavior and aggression are prominent symptoms in several psychiatric disorders including antisocial personality disorder. An established precursor to aggression is a frustrating event, which can elicit anger or exasperation, thereby prompting aggressive responses. While some studies have investigated the neural correlates of frustration and aggression, examination of their relation to trait aggression in healthy populations are rare. Based on a screening of 550 males, we formed two extreme groups, one including individuals reporting high (n=21) and one reporting low (n=18) trait aggression. Using functional magnetic resonance imaging (fMRI) at 3T, all participants were put through a frustration task comprising unsolvable anagrams of German nouns. Despite similar behavioral performance, males with high trait aggression reported higher ratings of negative affect and anger after the frustration task. Moreover, they showed relatively decreased activation in the frontal brain regions and the dorsal anterior cingulate cortex (dACC) as well as relatively less amygdala activation in response to frustration. Our findings indicate distinct frontal and limbic processing mechanisms following frustration modulated by trait aggression. In response to a frustrating event, HA individuals show some of the personality characteristics and neural processing patterns observed in abnormally aggressive populations. Highlighting the impact of aggressive traits on the behavioral and neural responses to frustration in non-psychiatric extreme groups can facilitate further characterization of neural dysfunctions underlying psychiatric disorders that involve abnormal frustration processing and aggression.
Aggression is a common response to provocation, albeit with considerable interindividual differences. In this fMRI study, we investigated emotional reactivity to threat as possible link between provocation and aggression, as well as the neural correlates of this relationship. We hypothesized that emotional reactivity, measured as fear potentiation (FP) of the startle response, would be negatively associated with aggressive behavior and would modulate neural activity during an aggressive interaction. In 30 healthy female participants, FP was measured as the difference between blink amplitudes while watching threatening versus neutral pictures. Participants subsequently engaged in a variant of the Taylor Aggression Paradigm (TAP), while being scanned. During the TAP, participants selected a punishment level for either a highly provoking or a non-provoking opponent. There was no difference in aggressive behavior between participants high and low in FP. However, we found a negative correlation between FP and the neural provocation effect in several regions of a network previously associated with mentalizing including the medial prefrontal cortex, precuneus and the temporo-parietal junction. Independently of the FP variability, aggressive behavior correlated with the provocation effect on activity in the caudate nucleus. Our results indicate that during a provocative confrontation, high emotional reactivity to threat suppresses recruitment of the mentalizing network.
This chapter reviews the literature exploring the neural basis of self-control and asserts that the right ventrolateral prefrontal cortex (rVLPFC) is a neural region commonly recruited across many different forms of self-control. As used here, self-control is operationalized as inhibitory impulse control. This is one of multiple subprocesses of executive, or cognitive, control (Lenartowicz, Kalar, Congdon, & Poldrack, 2010; Sabb et al., 2008). This operationalization is motivated by the hypothesis addressed here that the rVLPFC underlies inhibitory control; thus, in the remainder of this chapter, we will use the term “self-control” to refer to inhibitory impulse control.
Behavioral research on emotion regulation thus far has focused on conscious and deliberative strategies such as reappraisal. Neuroscience investigations into emotion regulation have followed suit. However, neuroimaging tools now open the door to investigate more automatic forms of emotion regulation that take place incidentally and potentially outside of participant awareness that have previously been difficult to examine. The present paper reviews studies on the neuroscience of intentional/deliberate emotion regulation and identifies opportunities for future directions that have not yet been addressed. The authors suggest a broad framework for emotion regulation that includes both deliberative and incidental forms. This framework allows insights from incidental emotion regulation to address open questions about existing work, and vice versa. Several studies relevant to incidental emotion regulation are reviewed with the goal of providing an empirical and methodological groundwork for future research. Finally, several theoretical issues for incidental and intentional emotion regulation are discussed.
The present project utilized the Five Factor Model of personality (FFM; McCrae & Costa, 1990) to clarify the multi-faceted nature of impulsivity. The NEO-PI-R and a number of commonly used impulsivity measures were administered to over 400 young adults. Exploratory factor analyses identified four distinct personality facets associated with impulsive-like behavior which were labeled urgency, (lack of) premeditation, (lack of) perseverance, and sensation seeking. Each of these traits was marked by a different facet of the FFM. Following the initial factor identification, scales to measure each of the personality facets were created and combined to form the UPPS Impulsive Behavior scale. Implications for the understanding of impulsive behavior and the FFM are discussed, as are future applications of the UPPS impulsive behavior scale.
Conceptual and empirical approaches to the study of the role of asymmetric frontal cortical activity in emotional processes are reviewed. Although early research suggested that greater left than right frontal cortical activity was associated with positive affect, more recent research, primarily on anger, suggests that greater left than right frontal cortical activity is associated with approach motivation, which can be positive (e.g., enthusiasm) or negative in valence (e.g., anger). In addition to reviewing this research on anger, research on guilt, bipolar disorder, and various types of positive affect is reviewed with relation to their association with asymmetric frontal cortical activity. The reviewed research not only contributes to a more complete understanding of the emotive functions of asymmetric frontal cortical activity, but it also points to the importance of considering motivational direction as separate from affective valence in psychological models of emotional space.
It is well established that a lack of social support constitutes a major risk factor for morbidity and mortality, comparable to risk factors such as smoking, obesity, and high blood pressure. Although it has been hypothesized that social support may benefit health by reducing physiological reactivity to stressors, the mechanisms underlying this process remain unclear. Moreover, to date, no studies have investigated the neurocognitive mechanisms that translate experiences of social support into the health outcomes that follow. To investigate these processes, thirty participants completed three tasks in which daily social support, neurocognitive reactivity to a social stressor, and neuroendocrine responses to a social stressor were assessed. Individuals who interacted regularly with supportive individuals across a 10-day period showed diminished cortisol reactivity to a social stressor. Moreover, greater social support and diminished cortisol responses were associated with diminished activity in the dorsal anterior cingulate cortex (dACC) and Brodmann's area (BA) 8, regions previously associated with the distress of social separation. Lastly, individual differences in dACC and BA 8 reactivity mediated the relationship between high daily social support and low cortisol reactivity, such that supported individuals showed reduced neurocognitive reactivity to social stressors, which in turn was associated with reduced neuroendocrine stress responses. This study is the first to investigate the neural underpinnings of the social support-health relationship and provides evidence that social support may ultimately benefit health by diminishing neural and physiological reactivity to social stressors.
The relationship between anger and aggression is imperfect. Based on work on the neuroscience of anger, we predicted that
anger associated with greater relative left frontal cortical activation would be more likely to result in aggression. To test
this hypothesis, we combined transcranial direct current stimulation (tDCS) over the frontal cortex with interpersonal provocation.
Participants received insulting feedback after 15 min of tDCS and were able to aggress by administering noise blasts to the
insulting participant. Individuals who received tDCS to increase relative left frontal cortical activity behaved more aggressively
when they were angry. No relation between anger and aggression was observed in the increase relative right frontal cortical
activity or sham condition. These results concur with the motivational direction model of frontal asymmetry, in which left
frontal activity is associated with anger. We propose that anger with approach motivational tendencies is more likely to result
in aggression.
Effects of weak electrical currents on brain and neuronal function were first described decades ago. Recently, DC polarization of the brain was reintroduced as a noninvasive technique to alter cortical activity in humans. Beyond this, transcranial direct current stimulation (tDCS) of different cortical areas has been shown, in various studies, to result in modifications of perceptual, cognitive, and behavioral functions. Moreover, preliminary data suggest that it can induce beneficial effects in brain disorders. Brain stimulation with weak direct currents is a promising tool in human neuroscience and neurobehavioral research. To facilitate and standardize future tDCS studies, we offer this overview of the state of the art for tDCS.
Ostracism arouses negative affect. However, little is known about variables that influence the intensity of these negative
affective responses. Two studies fill this void by incorporating work on approach- and withdrawal-related emotional states
and their associated cortical activations. Study 1 found that following ostracism anger related directly to relative left
frontal cortical activation. Study 2 used unilateral hand contractions to manipulate frontal cortical activity prior to an
ostracizing event. Right-hand contractions, compared to left-hand contractions, caused greater relative left frontal cortical
activation during the hand contractions as well as ostracism. Also, right-hand contractions caused more self-reported anger
in response to being ostracized. Within-condition correlations revealed patterns of associations between ostracism-induced
frontal asymmetry and emotive responses to ostracism consistent with Study 1. Taken together, these results suggest that asymmetrical
frontal cortical activity is related to angry responses to ostracism, with greater relative left frontal cortical activity
being associated with increased anger.
According to sociometer theory, self-esteem serves as a barometer of the extent to which individuals are socially included or excluded by others. We hypothesized that trait self-esteem would be related to social pain responsiveness, and we used functional magnetic resonance imaging to experimentally investigate this potential relationship. Participants (n = 26) performed a cyberball task, a computerized game of catch during which the participants were excluded from the game. Participants then rated the degree of social pain experienced during both inclusion in and exclusion from the game. Individuals with lower trait self-esteem reported increased social pain relative to individuals with higher trait self-esteem, and such individuals also demonstrated a greater degree of dorsal anterior cingulate cortex activation. A psychophysiological interaction analysis revealed a positive connectivity between the dorsal anterior cingulate and prefrontal cortices for the lower trait self-esteem group, and a corresponding negative connectivity for the higher trait self-esteem group. Heightened dorsal anterior cortex activity and a corresponding connection with the prefrontal cortex might be one possible explanation for the greater levels of social pain observed experienced by individuals with low trait self-esteem.
Decision often implies a utilitarian choice based on personal gain, even at the expense of damaging others. Despite the social implications of utilitarian behavior, its neurophysiological bases remain largely unknown. To assess how the human brain controls utilitarian behavior, we delivered transcranial direct current stimulation (tDCS) over the ventral prefrontal cortex (VPC) and over the occipital cortex (OC) in 78 healthy subjects. Utilitarian judgment was assessed with the moral judgment task before and after tDCS. At baseline, females provided fewer utilitarian answers than males for personal moral dilemmas (p = .007). In males, VPC-tDCS failed to induce changes and in both genders OC-tDCS left utilitarian judgments unchanged. In females, cathodal VPC-tDCS tended to decrease whereas anodal VPC-tDCS significantly increased utilitarian responses (p = .005). In males and females, reaction times for utilitarian responses significantly decreased after cathodal (p<.001) but not after anodal (p = .735) VPC-tDCS. We conclude that ventral prefrontal tDCS interferes with utilitarian decisions, influencing the evaluation of the advantages and disadvantages of each option in both sexes, but does so more strongly in females. Whereas cathodal tDCS alters the time for utilitarian reasoning in both sexes, anodal stimulation interferes more incisively in women, modifying utilitarian reasoning and the possible consequent actions. The gender-related tDCS-induced changes suggest that the VPC differentially controls utilitarian reasoning in females and in males. The gender-specific functional organization of the brain areas involved in utilitarian behavior could be a correlate of the moral and social behavioral differences between the two sexes.
People feel psychological pain when they are excluded, and this pain is often attenuated when emotional support is received. It is therefore likely that a specific neural mechanism underlies the detection of social exclusion. Similarly, specific neural mechanisms may underlie the beneficial effects of emotional support. Although neuroimaging researchers have recently examined the neural basis of social pain, there is presently no agreement as to which part of the anterior cingulate cortex (ACC) is involved in the perception and modulation of social pain. We hypothesized that activity in those brain regions that are associated with social pain would be correlated with decrements in social pain induced by emotional support. To examine the effects of emotional support on social pain caused by exclusion, we conducted an fMRI study in which participants played a virtual ball-tossing game. Participants were initially included and later excluded from the game. In the latter half of the session from which participants were excluded, participants received emotionally supportive text messages. We found that emotional support led to increased activity in the left lateral/medial prefrontal cortices and some temporal regions. Those individuals who experienced greater attenuation of social pain exhibited lower ventral ACC and higher left lateral prefrontal cortex activation. These results suggest that the ventral ACC underlies social pain, and that emotional support enhances prefrontal cortex activity, which in turn may lead to a weakened affective response.
Neurocognitive studies have observed rIFC involvement in motor, cognitive, and affective inhibition, suggesting that rIFC is a common inhibitory mechanism across psychological domains. If true, intentional inhibition in one domain may have unintended inhibitory effects ("spillover") in other domains. The present study used an emotional go/no-go task that produces responses in both motor and affective domains, but induces intentional inhibition in only the motor domain. Data support the hypothesis that intentional inhibition in the motor domain, via rIFC, produces inhibitory spillover in the affective domain. Specifically, we observed increased rIFC along with reduced amygdala activity when participants intentionally inhibited motor responses during the presentation of negatively-valenced stimuli, and greater inverse connectivity between these regions during motor inhibition in a PPI analysis. Given the absence of intentional affect regulation, these results suggest that intentional inhibition of a motor response dampens the amygdala activation coincident with affective stimuli to the extent that rIFC activation is higher.
Distraction and reappraisal are two commonly used forms of cognitive emotion regulation. Functional neuroimaging studies have shown that each one depends upon interactions between pFC, interpreted as implementing cognitive control, and limbic regions, interpreted as mediating emotional responses. However, no study has directly compared distraction with reappraisal, and it remains unclear whether they draw upon different neural mechanisms and have different emotional consequences. The present fMRI study compared distraction and reappraisal and found both similarities and differences between the two forms of emotion regulation. Both resulted in decreased negative affect, decreased activation in the amygdala, and increased activation in prefrontal and cingulate regions. Relative to distraction, reappraisal led to greater decreases in negative affect and to greater increases in a network of regions associated with processing affective meaning (medial prefrontal and anterior temporal cortices). Relative to reappraisal, distraction led to greater decreases in amygdala activation and to greater increases in activation in prefrontal and parietal regions. Taken together, these data suggest that distraction and reappraisal differentially engage neural systems involved in attentional deployment and cognitive reframing and have different emotional consequences.
Successful control of affect partly depends on the capacity to modulate negative emotional responses through the use of cognitive
strategies (i.e., reappraisal). Recent studies suggest the involvement of frontal cortical regions in the modulation of amygdala
reactivity and the mediation of effective emotion regulation. However, within-subject inter-regional connectivity between
amygdala and prefrontal cortex in the context of affect regulation is unknown. Here, using psychophysiological interaction
analyses of functional magnetic resonance imaging data, we show that activity in specific areas of the frontal cortex (dorsolateral,
dorsal medial, anterior cingulate, orbital) covaries with amygdala activity and that this functional connectivity is dependent
on the reappraisal task. Moreover, strength of amygdala coupling with orbitofrontal cortex and dorsal medial prefrontal cortex
predicts the extent of attenuation of negative affect following reappraisal. These findings highlight the importance of functional
connectivity within limbic-frontal circuitry during emotion regulation.
The authors assessed whether low executive cognitive functioning (ECF) and a difficult temperament are related to aggressive and nonaggressive forms of antisocial behavior (ASB) in 249, 14-18-year-old, conduct-disordered females and controls. ECF was measured using neuropsychological tests; temperament was measured using the Dimensions of Temperament Survey-revised; and ASB was assessed using psychiatric symptom counts for conduct disorder. The conduct-disordered females exhibited lower ECF capacity and a greater difficult temperament compared with the controls. The combined influence of low ECF and difficult temperament was significantly related to both forms of ASB. In comparison with low ECF, difficult temperament was more strongly related to nonaggressive ASB, whereas in comparison with difficult temperament, low ECF was more strongly related to aggressive ASB. Last, ECF mediated the relation between difficult temperament and aggressive ASB.
In this paper we demonstrate in the intact human the possibility of a non-invasive modulation of motor cortex excitability by the application of weak direct current through the scalp. Excitability changes of up to 40 %, revealed by transcranial magnetic stimulation, were accomplished and lasted for several minutes after the end of current stimulation. Excitation could be achieved selectively by anodal stimulation, and inhibition by cathodal stimulation. By varying the current intensity and duration, the strength and duration of the after-effects could be controlled. The effects were probably induced by modification of membrane polarisation. Functional alterations related to post-tetanic potentiation, short-term potentiation and processes similar to postexcitatory central inhibition are the likely candidates for the excitability changes after the end of stimulation. Transcranial electrical stimulation using weak current may thus be a promising tool to modulate cerebral excitability in a non-invasive, painless, reversible, selective and focal way.
Laboratory measures play an important role in the study of aggression because they allow researchers to make causal inferences. However, these measures have also been criticized. In particular, the competitive reaction time task (CRTT) has been criticized for allowing aggression to be operationalized in multiple ways, leaving it susceptible to “p‐hacking.” This article describes the development of the CRTT and the ways in which its paradigm flexibility and analytic flexibility allows it to test a wide range of hypotheses and research questions. This flexibility gives the CRTT significant scientific utility, but as with any research paradigm, comes with the obligation that it has to be used with integrity. Although safeguards exist and there is little evidence of misuse, study preregistration can increase confidence in CRTT findings. The importance of findings such as those of Hyatt et al. (in press), which provide further evidence for the validity of the CRTT, are also noted.
Contemporary models of behavioral regulation maintain that balanced activity between cognitive control areas (prefrontal cortex, PFC) and subcortical reward-related regions (nucleus accumbens, NAC) mediates the selection of appropriate behavioral responses, whereas imbalanced activity (PFC < NAC) results in maladaptive behavior [1-6]. Imbalance can arise from reduced engagement of PFC (via fatigue or stress [7]) or from excessive activity in NAC [8]. Additionally, a concept far less researched is that an imbalance can result from simultaneously low PFC activity and high NAC activity. This occurs during adolescence, when the maturation of PFC lags behind that of NAC and NAC is more functionally active compared to adulthood or pre-adolescence [2, 5, 9, 10]. Accordingly, activity is disproportionately higher in NAC than in PFC, which may contribute to impulsivity and risk-taking exhibited by adolescents [5, 6, 10-12]. Despite having explanatory value, support for this notion has been solely correlational. Here, we causally tested this using chemogenetics to simultaneously decrease neural activity in the orbitofrontal cortex (OFC) and increase activity in NAC in adult rats, mimicking the imbalance during adolescence. We tested the effects on negative occasion setting, an important yet understudied form of inhibitory learning that may be particularly relevant during adolescence. Rats with combined manipulation of OFC and NAC were impaired in learning to use environmental cues to withhold a response, an effect that was greater than that of either manipulation alone. These findings provide direct evidence that simultaneous underactivity in OFC and overactivity in NAC can negatively impact behavioral control and provide insight into the neural systems that underlie inhibitory learning.
The Tangram Help/Hurt Task is a laboratory-based measure designed to simultaneously assess helpful and hurtful behavior. Across five studies we provide evidence that further establishes the convergent and discriminant validity of the Tangram Help/Hurt Task. Cross-sectional and meta-analytic evidence finds consistently significant associations between helpful and hurtful scores on the Tangram Task and prosocial and aggressive personality traits. Experimental evidence reveals that situational primes known to induce aggressive and prosocial behavior significantly influence helpful and hurtful scores on the Tangram Help/Hurt Task. Additionally, motivation items in all studies indicate that tangram choices are indeed associated with intent of helping and hurting. We discuss the advantages and limitations of the Tangram Help/Hurt Task relative to established measures of helpful and hurtful behavior. Aggr. Behav. 9999:1–14, 2016.
The capacity for self-regulation allows people to control their thoughts, behaviors, emotions, and desires. In spite of this impressive ability, failures of self-regulation are common and contribute to numerous societal problems, from obesity to drug addiction. Such failures frequently occur following exposure to highly tempting cues, during negative moods, or after self-regulatory resources have been depleted. Here we review the available neuroscientific evidence regarding self-regulation and its failures. At its core, self-regulation involves a critical balance between the strength of an impulse and an individual's ability to inhibit the desired behavior. Although neuroimaging and patient studies provide consistent evidence regarding the reward aspects of impulses and desires, the neural mechanisms that underlie the capacity for control have eluded consensus, with various executive control regions implicated in different studies. We outline the necessary properties for a self-regulation control system and suggest that the use of resting-state functional connectivity analyses may be useful for understanding how people regulate their behavior and why they sometimes fail in their attempts. Expected final online publication date for the Annual Review of Neuroscience Volume 38 is July 08, 2015. Please see http://www.annualreviews.org/catalog/pubdates.aspx for revised estimates.
Purpose
Three-dimensional (3D) numerical computation of electric fields generated by transcranial direct current stimulation (tDCS) has widened our insight into the underlying mechanisms of current conduction, accelerated the development of novel electrode montages, and enabled more accurate field concentrations to targeted brain areas. However, there is no well-established field simulator specifically designed to analyze electric fields due to tDCS.
Methods
We developed a MATLAB-based toolbox, COMETS (COMputation of Electric field due to Transcranial current Stimulation), for simulating local electric fields generated by tDCS. Since COMETS has a simple and interactive graphical user interface, users can readily simulate various electrode configurations, sizes, and orientations without coding any MATLAB scripts. COMETS evaluates 3D cortical current distributions based on the electrostatic finite element method (FEM).
Results
Although only a standard human head model is provided in the current version, users may import their own head model datasets for specific research. For advanced 3D visualization of the resultant cortical current distributions, output data can also be exported to readily accessible ASCII-format data files. The toolbox package is freely available at http://www.COMETStool.com for noncommercial and academic uses.
Conclusions
It is expected that our toolbox COMETS can contribute to popularizing the numerical analysis of cortical stimulation current in the field of noninvasive electrical brain stimulation.
Resting anterior brain electrical activity, self-report measures of Behavioral Approach and Inhibition System (BAS and BIS) strength, and general levels of positive and negative affect (PA and NA) were collected from 46 unselected undergraduates on two separate occasions Electroencephalogram (EEG) measures of prefrontal asymmetry and the self-report measures showed excellent internal consistency reliability and adequate test-retest stability Aggregate measures across the two assessments were computed for all indices Subjects with greater relative left prefrontal activation reported higher levels of BAS strength, whereas those with greater relative right prefrontal activation reported higher levels of BIS strength Prefrontal EEG asymmetry accounted for more than 25% of the variance in the self-report measure of relative BAS-BIS strength Prefrontal EEG, however, was not significantly correlated with PA or NA, or the relative strength of PA versus NA Posterior asymmetry was unrelated to the self-report measures
The electric field in the cortex during transcranial current stimulation was calculated based on a realistic head model derived from structural MR images. The aim of this study was to investigate the effect of tissue heterogeneity and of the complex cortical geometry on the electric field distribution. To this end, the surfaces separating the different tissues were represented as accurately as possible, particularly the cortical surfaces. Our main finding was that the complex cortical geometry combined with the high conductivity of the CSF which covers the cortex and fills its sulci gives rise to a very distinctive electric field distribution in the cortex, with a strong normal component confined to the bottom of sulci under or near the electrodes and a weaker tangential component that covers large areas of the gyri that lie near each electrode in the direction of the other electrode. These general features are shaped by the details of the sulcal and gyral geometry under and between the electrodes. Smaller electrodes resulted in a significant improvement in the focality of the tangential component but not of the normal component, when focality is defined in terms of percentages of the maximum values in the cortex. Experimental validation of these predictions could provide a better understanding of the mechanisms underlying the acute effects of tCS.
The current study attempts to clarify the multi-faceted nature of impulsivity through the use of the four-factor UPPS Impulsive Behaviour scale. In order to build the nomological network surrounding this scale, the UPPS was administered to individuals with borderline personality disorder (BPD), pathological gamblers (PG), alcohol abusers (divided into two groups based on the presence of antisocial features), and a control group. Several of the UPPS scales (e.g. Urgency, lack of Premeditation, and Sensation Seeking) differentiated the BPD, PG, and alcohol abusers with antisocial features from a group of non-antisocial alcohol abusers and a control group. Overall, the UPPS scales accounted for between 7% (pathological gambling) and 64% (borderline personality disorder features) of the overall variance in the psychopathology measures. Individual UPPS scales also made unique contributions to several of these disorders, which may provide insight into which of these personality traits may predispose individuals to behave in maladaptive or problematic ways. The results provide support for the differentiation of impulsivity-related constructs into the current four-factor model. Copyright © 2005 John Wiley & Sons, Ltd.
Anterior brain asymmetry, assessed through the alpha and beta band in resting-state electroencephalogram (EEG) is associated with approach-related behavioral dispositions, particularly with aggression in the general population. To date, the association between frontal asymmetry and aggression has not been examined in highly aggressive groups. We examined the topographic characteristics of alpha and beta activity, the relation of both asymmetry metrics to trait aggression, and whether alpha asymmetry was extreme in anterior regions according to clinical standards in a group of imprisoned violent offenders. As expected, these individuals were characterized by stronger right than left-hemispheric alpha activity, which was putatively extreme in anterior regions in one third of the cases. We also report that in line with observations made in the general population, aggression was associated with stronger right-frontal alpha activity in these violent individuals. This suggests that frontal alpha asymmetry, as a correlate of trait aggression, might be utilizable as an outcome measure in studies which assess the effects of anti-aggressiveness training in violent offenders.
Among the most popular measures of aggression is the 29-item, self-report Aggression Questionnaire (AQ; Buss & Perry, 1992; Buss & Warren, 2000). Structural analyses of the AQ have revealed four underlying factors: Physical Aggression, Verbal Aggression, Anger, and Hostility. However, these four factors explain too little common variance (i.e., about 80%) to be an adequate measurement model. In the present study, we used confirmatory factor analysis with a total sample of 1154 respondents to compare four alternative measurement models for the AQ that are currently in use. Replicating earlier work, none of these models fit the data well, and the original four-factor model achieved only mediocre goodness-of-fit in three independent samples (GFI = .76 − .81). To develop a more appropriate measurement model, we omitted items with low loadings or multiple loadings based on principal components analysis and excluded items with reverse-scored wording. This yielded a 12-item, four-factor measurement model with acceptable goodness-of-fit (GFI = .94). Secondary analysis of two independent data sets confirmed the refined model's generalizability for British (Archer, Holloway, & McLoughlin, 1995; GFI = .93) and Canadian (Harris, 1995; GFI = .94) samples. The refined model yielded equivalent factor structures for males and females in all three samples. We also replicated the refined four-factor model in two additional American samples, who completed a new short form of the AQ containing only the subset of 12 items in random order. Additional analyses provided evidence supporting the model's construct validity and demonstrated stronger discriminant validity for the refined Hostility factor compared to its predecessor. The new short form of the AQ thus not only contains fewer than half as many items as the original, but also is psychometrically superior.
The widespread, across-species strategy of stagewise escalation of aggression in agonistic encounters can be understood in terms of resource capture and control with least risk and cost. Human anger likely follows similar principles. As an adaptive phenomenon, escalation may involve particular neural circuitry. To advance beyond a standard view that the frontal lobe tonically inhibits subcortical circuits of aggression, a model is proposed which starts with the general rostrally directed flow of information in the brain. Earlier stage processing of visual and auditory input is transmitted from posterior and middle temporal cortices to anterior temporal lobe where rudimentary appraisals of threat and provocation are developed. These directly but diffusely activate cortical/subcortical anger/aggression response systems. At the same time, the anterior temporal loci transmit the modality-specific perceptual information to orbito-frontal cortex where it is integrated with information about, e.g., the opponent's relative dominance/social status and evaluated for likelihood of potential rewards and punishments associated with different modes of responding and so forth. These frontal areas then impose an inhibitory gating or modulation and focusing of activity initiated by the anterior temporal loci through their projections to GABAergic interneurons in the same cortical/subcortical circuits. Escalation occurs as the inhibition imposed by the frontal areas is progressively lifted. Exploration of the implications, applications and hypotheses flowing from this model will improve our understanding of the biologically important and socially significant phenomena of escalation.
Despite its increasing use in experimental and clinical settings, the cellular and molecular mechanisms underlying transcranial direct current stimulation (tDCS) remain unknown. Anodal tDCS applied to the human motor cortex (M1) improves motor skill learning. Here, we demonstrate in mouse M1 slices that DCS induces a long-lasting synaptic potentiation (DCS-LTP), which is polarity specific, NMDA receptor dependent, and requires coupling of DCS with repetitive low-frequency synaptic activation (LFS). Combined DCS and LFS enhance BDNF-secretion and TrkB activation, and DCS-LTP is absent in BDNF and TrkB mutant mice, suggesting that BDNF is a key mediator of this phenomenon. Moreover, the BDNF val66met polymorphism known to partially affect activity-dependent BDNF secretion impairs motor skill acquisition in humans and mice. Motor learning is enhanced by anodal tDCS, as long as activity-dependent BDNF secretion is in place. We propose that tDCS may improve motor skill learning through augmentation of synaptic plasticity that requires BDNF secretion and TrkB activation within M1.
Psychopathy is a developmental disorder marked by emotional hyporesponsiveness and an increased risk for instrumental and reactive aggression. The increased risk for reactive aggression is the focus of the current paper. It will be argued that the increased risk for reactive aggression does not relate to an increased sensitivity to threatening stimuli since psychopathy is associated with a reduced sensitivity to threat. Instead, it is argued that the increased risk for reactive aggression relates to an increased risk for frustration; i.e., the emotional state following the performance of an action in the expectation of a particular reward and not receiving this reward. Two impairments seen in psychopathy would increase the risk for frustration and consequent potential reactive aggression; impairments in stimulus-reinforcement learning and reversal learning. It is argued that both are known consequences of impairment in ventromedial prefrontal cortex, one of the regions principally implicated in psychopathy.
The ability to recognize facial expressions has been shown to be different between males and females. Here we aimed to explore further this matter and investigate whether the effects of tDCS applied over the superior temporal cortex differs between males and females during a facial expression go-no-go task. Fourteen healthy subjects were exposed to a facial expression go-no-go task while they received two different conditions of stimulation: anodal tDCS of the left temporal cortex (with cathodal stimulation of the right temporal cortex) and sham tDCS. The order of conditions was randomized and counterbalanced across subjects. During each stimulation session (after 5 min of stimulation), subjects underwent a go-no-go task. The results showed that women had significantly more correct answers when compared to men (p=0.03) that was independent of condition of stimulation and valence of figures. In addition, women made significantly less errors during temporal stimulation when compared to sham stimulation (p=0.009) when responding to sad faces. Similarly, men made significantly more errors during temporal active stimulation as compared with sham stimulation (p=0.004) when responding to sad faces. Our results confirmed the notion that performance to facial expression recognition is increased in females compared with males and that modulation of temporal cortex with tDCS leads to differential effects according to gender.
Although prefrontal cortex has been implicated in the cognitive regulation of emotion, the cortical-subcortical interactions that mediate this ability remain poorly understood. To address this issue, we identified a right ventrolateral prefrontal region (vlPFC) whose activity correlated with reduced negative emotional experience during cognitive reappraisal of aversive images. We then applied a pathway-mapping analysis on subcortical regions to locate mediators of the association between vlPFC activity and reappraisal success (i.e., reductions in reported emotion). Results identified two separable pathways that together explained approximately 50% of the reported variance in self-reported emotion: (1) a path through nucleus accumbens that predicted greater reappraisal success, and (2) a path through ventral amygdala that predicted reduced reappraisal success (i.e., more negative emotion). These results provide direct evidence that vlPFC is involved in both the generation and regulation of emotion through different subcortical pathways, suggesting a general role for this region in appraisal processes.
As decision-making is central to motivated behavior, understanding its neural substrates can help elucidate the deficits that characterize various maladaptive behaviors. Twenty healthy adults performed a risk-taking task during positron emission tomography with (15)O-labeled water. The task, a computerized card game, tests the ability to weigh short-term rewards against long-term losses. A control task matched all components of the risk-taking task except for decision-making and the difference between responses to contingent and non-contingent reward and punishment. Decision-making (2 runs of the active task minus 2 runs of the control task) activated orbital and dorsolateral prefrontal cortex, anterior cingulate, insula, inferior parietal cortex and thalamus predominantly on the right side, and cerebellum predominantly on the left side. In an exploratory analysis, guessing (run 1 minus run 2 of the active task) accompanied activation of sensory-motor associative areas, and amygdala on the left side, whereas informed decision-making (run 2 minus run 1) activated areas that subserve memory (hippocampus, posterior cingulate) and motor control (striatum, cerebellum). The findings provide a framework for future investigations of decision-making in maladaptive behaviors.