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The Contribution of Non-invasive Brain Stimulation to the Study of the Neural Bases of Creativity and Aesthetic Experience
Abstract
Non-invasive brain stimulation (NIBS) techniques, such as transcranial magnetic stimulation (TMS) and transcranial electrical stimulation (tES), are widely employed in cognitive neuroscience to identify causal links between specific brain structures supporting sensory, motor, cognitive and affective functions. During the last decade, NIBS techniques have been increasingly applied to the study of the neural basis of creative thinking and aesthetic perception and appreciation. The present chapter offers an overview of mechanisms of actions of TMS and different types of tES and considers recent studies applying these techniques to shed light on the neural underpinning mediating creativity and the emergence of aesthetic experience. Available findings suggest the existence of some areas of overlap between the neural correlates of creativity and aesthetic experience mainly within prefrontal and parietal cortices (core nodes of the executive control and default mode networks); however, sensorimotor regions and low-level visual areas seem to be selectively dedicated to aesthetic experience of visual stimuli. In the concluding part, we consider current limitations and challenges in using NIBS and suggest future avenues for scientific exploration within these fields to fully exploit the great potential of brain stimulation to the study of the neural bases of creativity and aesthetic experiences.
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Neuroimaging and transcranial direct current stimulation (tDCS) research has revealed that generating novel ideas is associated with both reductions and increases in prefrontal cortex (PFC) activity, and engagement of posterior occipital cortex, among other regions. However, there is substantial variability in the robustness of these tDCS‐induced effects due to heterogeneous sample sizes, different creativity measures, and methodological diversity in the application of tDCS across laboratories. To address these shortcomings, we used twelve different montages within a standardized tDCS protocol to investigate how altering activity in frontotemporal and occipital cortex impacts creative thinking. Across four experiments, 246 participants generated either the common or an uncommon use for 60 object pictures while undergoing tDCS. Participants also completed a control short-term memory task. We applied active tDCS for 20 min at 1.5 mA through two 5 cm × 5 cm electrodes over left or right ventrolateral prefrontal (areas F7, F8) or occipital (areas O1, O2) cortex, concurrent bilateral stimulation of these regions across polarities, or sham stimulation. Cathodal stimulation of the left, but not right, ventrolateral PFC improved fluency in creative idea generation, but had no effects on originality, as approximated by measures of semantic distance. No effects were obtained for the control tasks. Concurrent bilateral stimulation of the ventrolateral PFC regardless of polarity direction, and excitatory stimulation of occipital cortex did not alter task performance. Highlighting the importance of cross-experimental methodological consistency, these results extend our past findings and contribute to our understanding of the role of left PFC in creative thinking.
The left angular gyrus (AG), part of the frontotemporal network, is implicated in creative thinking, including verbal creativity tasks such as novel metaphor generation. The current study tested the effects of tDCS over the left AG on two metaphor generation tasks. The study was a randomized, double-blind, sham-controlled, crossover study of anodal vs. cathodal stimulation by tDCS. Compared to sham, cathodal stimulation resulted in significantly increased novel metaphor generation, while anodal stimulation increased conventional metaphor generation. Higher motivation (behavioral approach system’s “fun-seeking”) was associated with greater metaphor creativity in the sham condition, and lower fun seeking was associated with producing a greater quantity of conventional metaphors. Following active stimulation, motivation traits no longer contributed to creative metaphor generation. Thus, the beneficial effect of cathodal tDCS over the left AG in generation of novel metaphors is through restraining the control network. The current study gives a glimpse into the neural basis for creative thinking.
Variations in head and brain anatomy determine the strength and distribution of electrical fields in humans and may account for inconsistent behavioral and neurophysiological results in transcranial electrical stimulation (tES) studies. However, it is insufficiently understood which anatomical features contribute to the variability of the modelled electric fields, and if their impact varies across age groups. In the present study, we tested the associations of global head anatomy, indexed by extra- and intra-cranial volumes, with electric field measures, comparing young and older adults. We modelled six “conventional” electrode montages typically used in tES studies using SimNIBS software in 40 individuals (20 young, 20 older adults; 20-35, 64-79 years). We extracted individual electric field strengths and focality values for each montage to identify tissue volumes that account for variability of the induced electric fields in both groups. Linear mixed models explained most of the inter-individual variability of the overall induced field strength in the brain, but not of field focality. Higher absolute head volume and relative volume of skin, skull and cerebrospinal fluid (CSF) were associated with lower overall electric field strengths. Additionally, we found interactions of age group with head volume and CSF, indicating that this relationship was mitigated in the older group. Our results demonstrate the importance to adjust brain stimulation not only according to brain atrophy, but also to additional parameters of head anatomy. Future studies need to elucidate the mechanisms underlying individual variability of tES effects in young and older adults, and verify the usefulness of the proposed models in terms of neurophysiology and behavior in empirical studies.
Background: Transcranial focused ultrasound (tFUS) is a noninvasive brain stimulation method that may modulate deep brain structures. This study investigates whether sonication of the right anterior thal-amus would modulate thermal pain thresholds in healthy individuals.
Methods: We enrolled 19 healthy individuals in this three-visit, double-blind, sham-controlled, crossover trial. Participants first underwent a structural MRI scan used solely for tFUS targeting. They then attended two identical experimental tFUS visits (counterbalanced by condition) at least one week apart. Within the MRI scanner, participants received two, 10-min sessions of either active or sham tFUS spread 10 min apart targeting the right anterior thalamus [fundamental frequency: 650 kHz, Pulse repetition frequency: 10 Hz, Pulse Width: 5 ms, Duty Cycle: 5%, Sonication Duration: 30s, Inter-Sonication Interval: 30 s, Number of Sonications: 10, ISPTA. 0 995 mW/cm2, ISPTA. 3 719 mW/cm2, Peak rarefactional pressure 0.72 MPa]. The primary outcome measure was quantitative sensory thresholding (QST), measuring sensory, pain, and tolerance thresholds to a thermal stimulus applied to the left forearm before and after right anterior thalamic tFUS.
Results: The right anterior thalamus was accurately sonicated in 17 of the 19 subjects. Thermal pain sensitivity was significantly attenuated after active tFUS. The pre-post x active-sham interaction was significant (F(1,245.95) ¼ 4.03, p ¼ .046). This interaction indicates that in the sham stimulation condition , thermal pain thresholds decreased 1.08 C (SE ¼ 0.28) pre-post session, but only decreased .51 C (SE ¼ 0.30) pre-post session in the active stimulation group.
Conclusions: Two 10-min sessions of anterior thalamic tFUS induces antinociceptive effects in healthy individuals. Future studies should optimize the parameter space, dose and duration of this effect which may lead to multi-session tFUS interventions for pain disorders.
Aesthetic appraisal of artwork can present the observer with visual problems to solve in the process of grasping its meaning and ‘visual rightness’ (i.e. “good” structure; Locher, 2003), with an elaboration on perceptual, semantic and affective dimensions (e.g. Marković, 2011). Thus observer's expertise is a factor in aesthetic appraisal. To examine the influence of art training on the aesthetic response, and to clarify the nature of the Representational/Abstract distinction, 30 Experts and 33 Non-experts (Art and Psychology students, respectively) were asked to rate 24 paintings on six affective and affective-evaluative semantic differential scales. Stimuli were images of paintings from the period 1900–1935, 12 broadly Representational and 12 broadly Abstract. Relative to Non-experts, Experts rated Abstract artworks as more Interesting, Beautiful, Informative and Sophisticated, distinguishing them less markedly from Representational artworks. Aggregate Expert and Non-expert ratings, processed by factor analysis, resulted in a two-factor solution. The first factor, contrasting Abstract and Representational artworks, appeared more salient for Non-experts. The second factor, Cool–Warm, separating vibrantly-colored paintings from those with a blue-dominated/dull palette, was more salient for Experts. While Non-experts exaggerated differences between Abstract and Representational paintings, Experts appraised these two types of art similarly, attending more to artwork collative properties. We conclude that appreciation of art by Experts involves ‘cognitive mastery’ (Leder, Belke, Oeberst, & Augustin, 2004), i.e. more complex, cues-based visual schemata which equip them with more sophisticated strategies for analysing collative properties and semantics of an artwork while parsing ‘visual rightness’ to unfold its visual meaning.
Human creative thinking is unique and capable of generating novel and valuable ideas. Recent research has clarified the contribution of different brain networks (default mode network, DN; executive control network; salience network) to creative thinking. However, the effects of brain stimulation on brain networks during creative thinking and on creative performance have not been clarified. The present study was designed to examine the changes in functional connectivity (FC) and effective connectivity (EC) of the large-scale brain network, and the ensuing changes in creative performance, induced by transcranial direct current stimulation (tDCS). Fourteen healthy male students underwent two tDCS sessions, one with actual stimulation and one with sham stimulation, on two separate days. Participants underwent tDCS (anode over the left dorsolateral prefrontal cortex, DLPFC; cathode over the right inferior parietal lobule, IPL) for 20 min. Before and after the tDCS session, electroencephalography signals were acquired from 32 electrodes over the whole head during the creative thinking task. On FC analysis, the delta band FC between the posterior cingulate cortex and IPL significantly increased only after real stimulation. We also found that the change of flexibility score was significantly correlated with the change in: (i) delta band FC between mPFC and left lateral temporal cortex (LTC) and (ii) alpha band FC between IPL and right LTC. On EC analysis, decreased flow within the DN (from left LTC to right IPL) was observed. Our results reveal that tDCS could affect brain networks, particularly the DN, during creative thinking and modulate key FC in the generation of flexible creative ideas.
Creativity pervades many areas of everyday life and is considered highly relevant in several human living domains. Previous literature suggests that the posterior parietal cortex (PPC) is related to creativity. However, none of previous studies have compared the effect of transcranial random noise stimulation (tRNS) over bilateral PPC on both verbal and visual divergent thinking (DT) and Remote Associates Test (RAT) in the same experimental design. Forty healthy participants were randomly assigned to tRNS (100-500 Hz) over bilateral PPC or sham group, for 15 min and current was set at 1.5 mA. Participants' creativity skills were assessed before and after brain stimulation with the Unusual Uses and the Picture Completion subtests from the Torrance Test of Creative Thinking and the RAT. ANCOVA (baseline scores as covariate) results indicated that tRNS group had significantly higher scores at post-test in RAT and visual originality compared to sham group. Unusual Uses, on the other hand, was not significant. Improvement in RAT suggests the involvement of PPC during via insight solution which may reflect internally directed attention that helps the recombination of remotely associated information. The improvement in visual originality dimension from DT may be due to a higher internally directed attention while reducing externally oriented attention.
Background
Transcranial direct current stimulation (tDCS) has been shown to improve working memory (WM) performance in healthy individuals, however effects tend to be modest and variable. Transcranial random noise stimulation (tRNS) can be delivered with a direct-current offset (DC-offset) to induce equal or even greater effects on cortical excitability than tDCS. To-date, no research has directly compared the effects of these techniques on WM performance or underlying neurophysiological activity.
Objective
To compare the effects of anodal tDCS, tRNS + DC-offset, or sham stimulation over the left dorsolateral prefrontal cortex (DLPFC) on WM performance and task-related EEG oscillatory activity in healthy adults.
Methods
Using a between-subjects design, 49 participants were allocated to receive either anodal tDCS (N = 16), high-frequency tRNS + DC-offset (N = 16), or sham stimulation (N = 17) to the left DLPFC. Changes in WM performance were assessed using the Sternberg WM task completed before and 5- and 25-minutes post-stimulation. Event-related synchronisation/desynchronisation (ERS/ERD) of oscillatory activity was analysed from EEG recorded during WM encoding and maintenance.
Results
tRNS induced more pronounced and consistent enhancements in WM accuracy when compared to both tDCS and sham stimulation. Improvements in WM performance following tRNS were accompanied by increased theta ERS and diminished gamma ERD during WM encoding, which were significantly greater than those observed following anodal tDCS or sham stimulation.
Conclusions
These findings demonstrate the potential of tRNS + DC-offset to modulate cognitive and electrophysiological measures of WM and raise the possibility that tRNS + DC-offset may be more effective and reliable than tDCS for enhancing WM performance in healthy individuals.
Noninvasive brain stimulation (NIBS) techniques, such as transcranial magnetic stimulation or transcranial direct and alternating current stimulation, are advocated as measures to enable causal inference in cognitive neuroscience experiments. Transcending the limitations of purely correlative neuroimaging measures and experimental sensory stimulation, they allow to experimentally manipulate brain activity and study its consequences for perception, cognition, and eventually, behavior. Although this is true in principle, particular caution is advised when interpreting brain stimulation experiments in a causal manner. Research hypotheses are often oversimplified, disregarding the underlying (implicitly assumed) complex chain of causation, namely, that the stimulation technique has to generate an electric field in the brain tissue, which then evokes or modulates neuronal activity both locally in the target region and in connected remote sites of the network, which in consequence affects the cognitive function of interest and eventually results in a change of the behavioral measure. Importantly, every link in this causal chain of effects can be confounded by several factors that have to be experimentally eliminated or controlled to attribute the observed results to their assumed cause. This is complicated by the fact that many of the mediating and confounding variables are not directly observable and dose–response relationships are often nonlinear. We will walk the reader through the chain of causation for a generic cognitive neuroscience NIBS study, discuss possible confounds, and advise appropriate control conditions. If crucial assumptions are explicitly tested (where possible) and confounds are experimentally well controlled, NIBS can indeed reveal cause–effect relationships in cognitive neuroscience studies.
Divergent thinking (DT) as one component of creativity is the ability to search for multiple solutions to a single problem and is reliably tested with the Alternative Uses Task (AUT). DT depends on activity in the inferior frontal gyrus (IFG), a prefrontal region that has also been associated with inhibitory control (IC). Experimentally manipulating IC through transcranial direct current stimulation (tDCS) led to alterations in DT. Here, we aimed at further examining such potential mediating effects of IC on DT (measured as flexibility, fluency, and originality in the AUT) by modulating IC tDCS.
Participants received either cathodal tDCS (c-tDCS) of the left IFG coupled with anodal tDCS (a-tDCS) of the right IFG (L-R+; N = 19), or the opposite treatment (L+R-; N = 21). We hypothesized that L+R- stimulation would enhance IC assessed with the Go NoGo task (GNGT), and that facilitated IC would result in lower creativity scores. The reversed stimulation arrangement (i.e., L-R+) should result in higher creativity scores.
We found that tDCS only affected the originality component of the AUT but not flexibility or fluency. We also found no effects on IC, and thus, the mediation effect of IC could not be confirmed. However, we observed a moderation effect: Inhibition of left and facilitation of right IFG (L-R+) resulted in enhanced flexibility and originality scores, only when IC performance was also improved.
We conclude that inducing a right-to-left gradient in IFG activity by tDCS is efficient in enhancing DT, but only under conditions where tDCS is sufficient to alter IC performance as well.
Processing of ambiguous visual stimuli has been associated with an increased activation of the left lateral prefrontal cortex (PFC) in neuroimaging studies. Nevertheless, the functional role of prefrontal activity in this process is not fully understood. In this experiment we asked participants to evaluate ambiguous inkblots from the Rorschach test, while stimulating the left lateral PFC using excitatory anodal transcranial direct current stimulation (tDCS). In addition, visual insight ability was assessed as a control measure requiring visual and conceptual restructuring and convergent thinking rather than divergent idea generation employed to interpret the equivocal Rorschach inkblots. Using a randomized double-blind design, we demonstrated that anodal tDCS increased the number of meaningful patterns recognized in the inkblots but had no significant effect on visual insight. These findings support the role of left lateral PFC in the processing of ambiguous visual information and object recognition. More generally, we discuss that the PFC may be involved in the mechanisms supporting the activation of stored visual and semantic representations in order to compensate for less informative bottom-up inputs and thus facilitate flexible cognition and idea generation.
The brain is organized into networks that reorganize dynamically in response to cognitive demands and exogenous stimuli. In recent years, repetitive transcranial magnetic stimulation (rTMS) has gained increasing use as a noninvasive means to modulate cortical physiology, with effects both proximal to the stimulation site and in distal areas that are intrinsically connected to the proximal target. In light of these network-level neuromodulatory effects, there has been a rapid growth in studies attempting to leverage information about network connectivity to improve neuromodulatory control and intervention outcomes. However, the mechanisms-of-action of rTMS on network-level effects remain poorly understood and is based primarily on heuristics from proximal stimulation findings. To help bridge this gap, the current paper presents a systematic review of 33 rTMS studies with baseline and post-rTMS measures of fMRI resting-state functional connectivity (RSFC). Literature synthesis revealed variability across studies in stimulation parameters, studied populations, and connectivity analysis methodology. Despite this variability, it is observed that active rTMS induces significant changes on RSFC, but the prevalent low-frequency-inhibition/high-frequency-facilitation heuristic endorsed for proximal rTMS effects does not fully describe distal connectivity findings. This review also points towards other important considerations, including that the majority of rTMS-induced changes were found outside the stimulated functional network, suggesting that rTMS effects tend to spread across networks. Future studies may therefore wish to adopt conventions and systematic frameworks, such as the Yeo functional connectivity parcellation atlas adopted here, to better characterize network-level effect that contribute to the efficacy of these rapidly developing noninvasive interventions.
Much evidence suggests that the angular gyrus (AnG) is involved in episodic memory, but its precise role has yet to be determined. We examined two possible accounts within the same experimental paradigm: the "cortical binding of relational activity" (CoBRA) account (Shimamura, 2011), which suggests that the AnG acts as a convergence zone that binds multimodal episodic features, and the subjectivity account (Yazar et al., 2012), which implicates AnG involvement in subjective mnemonic experience (such as vividness or confidence). fMRI was used during both encoding and retrieval of paired associates. During study, female and male human participants memorized picture-pairs of common objects (in the unimodal task) or of an object-picture and an environmental sound (in the crossmodal task). At test, they performed a cued-recall task and further indicated the vividness of their memory. During retrieval, BOLD activation in the AnG was greatest for vividly remembered associates, consistent with the subjectivity account. During encoding, the same effect of vividness was found, but this was further modulated by task: greater activations were associated with subsequent recall in the crossmodal than the unimodal task. Therefore, encoding data suggest an additional role to the AnG in crossmodal integration, consistent with its role at retrieval proposed by CoBRA. These results resolve some of the puzzles in the literature and indicate that the AnG can play different roles during encoding and retrieval as determined by the cognitive demands posed by different mnemonic tasks.
Fluid intelligence (gf) represents a crucial component of human cognition, as it correlates with academic achievement, successful aging, and longevity. However, it has strong resilience against enhancement interventions, making the identification of gf enhancement approaches a key unmet goal of cognitive neuroscience. Here, we applied a spike-timing-dependent plasticity (STDP)-inducing brain stimulation protocol, named cortico-cortical paired associative stimulation (cc-PAS), to modulate gf in 29 healthy young subjects (13 females-mean ± standard deviation, 25.43 years ± 3.69), based on dual-coil transcranial magnetic stimulation (TMS). Pairs of neuronavigated TMS pulses (10-ms interval) were delivered over two frontoparietal nodes of the gf network, based on individual functional magnetic resonance imaging data and in accordance with cognitive models of information processing across the prefrontal and parietal lobe. cc-PAS enhanced accuracy at gf tasks, with parieto-frontal and fronto-parietal stimulation significantly increasing logical and relational reasoning, respectively. Results suggest the possibility of using SPTD-inducing TMS protocols to causally validate cognitive models by selectively engaging relevant networks and manipulating interregional temporal dynamics supporting specific cognitive functions.
Online repetitive transcranial magnetic stimulation (rTMS), applied while subjects are performing a task, is widely used to disrupt brain regions underlying cognition. However, online rTMS has also induced "paradoxical enhancement". Given the rapid proliferation of this approach, it is crucial to develop a better understanding of how online stimulation influences cognition, and the optimal parameters to achieve desired effects. To accomplish this goal, a quantitative meta-analysis was performed with random-effects models fitted to reaction time (RT) and accuracy data. The final dataset included 126 studies published between 1998 and 2016, with 244 total effects for reaction times, and 202 for accuracy. Meta-analytically, rTMS at 10 Hz and 20 Hz disrupted accuracy for attention, executive, language, memory, motor, and perception domains, while no effects were found with 1 Hz or 5 Hz. Stimulation applied at and 10 and 20 Hz slowed down RTs in attention and perception tasks. No performance enhancement was found. Meta-regression analysis showed that fMRI-guided targeting and short inter-trial intervals are associated with increased disruptive effects with rTMS.
The prefrontal‐limbic network in the human brain plays a major role in social cognition, especially cognitive control of emotion. The medial frontopolar cortex (mFP; Brodmann Area 10) and the amygdala are part of this network and display correlated neuronal activity in time, as measured by functional magnetic resonance imaging (fMRI). This functional connectivity is dynamic, sensitive to training, and affected in mental disorders. However, the effects of neurostimulation on functional connectivity within this network have not yet been systematically investigated. Here, we investigate the effects of both low‐ and high‐frequency repetitive transcranial magnetic stimulation (rTMS) to the right mFP on functional connectivity between mFP and amygdala, as measured with resting state fMRI (rsfMRI). Three groups of healthy participants received either low‐frequency rTMS (1 Hz; N = 18), sham TMS (1 Hz, subthreshold; N = 18) or high‐frequency rTMS (20 Hz; N = 19). rsfMRI was acquired before and after (separate days). We hypothesized a modulation of functional connectivity in opposite directions compared to sham TMS through adjustment of the stimulation frequency. Groups differed in functional connectivity between mFP and amygdala after stimulation compared to before stimulation (low‐frequency: decrease, high‐frequency: increase). Motion or induced changes in neuronal activity were excluded as confounders. Results show that rTMS is effective for increasing and decreasing functional coherence between prefrontal and limbic regions. This finding is relevant for social and affective neuroscience as well as novel treatment approaches in psychiatry.
Creativity has previously been shown to improve after the application of direct and alternating current transcranial stimulation over the dorsolateral prefrontal cortex (DLPFC). However, previous studies have not tested whether transcranial random noise stimulation (tRNS) was efficient for this purpose. The aim of this randomized, double-blind, placebo-controlled study was to investigate the effect of tRNS on both verbal convergent and (verbal and visual) divergent thinking during left DLPFC tRNS stimulation. Thirty healthy participants were randomly allocated to either a tRNS active group or a sham group. Each session lasted 20 min and the current was set to 1.5 mA (100–500 Hz). Participants’ verbal convergent thinking was assessed with the Remote Associates Test (RAT). Verbal and visual divergent thinking were respectively measured by using the Unusual Uses and Picture Completion subtests from the Torrance Tests of Creative Thinking. Bootstrapped analysis of variance showed significant differences in the mean change scores between the active tRNS group and the sham group in RAT scores (d = 1.68); unusual uses: fluency (d = 2.29) and originality (d = 1.43); and general creativity (d = 1.45). Visual divergent thinking, in contrast, did not show any significant improvement. Our results suggested that tRNS over the left DLPFC is effective for increasing verbal divergent and convergent thinking.
The investigation of the neural correlates of creative cognition requires researchers to adapt creativity tasks to meet the constraints imposed by cognitive neuroscience research—assessing well-defined cognitive processes, repeated over many tasks. We present a brief review of essential study design parameters in neuroscience research on creativity, including number of task repetitions (i.e., trials), time on task, what kind of responses are collected (e.g., whether participants speak, write, draw, press buttons), and when these responses are collected (e.g., after or during task). We further examine how design parameters depend on neuroscience methods (e.g., fMRI, EEG) and task type (e.g., divergent thinking, creative problem solving). The review discloses a substantial heterogeneity of methodological approaches across studies but also identifies some established common practices. Typical adaptations include the employment of shortened tasks, which allows the realization of more tasks per session, and a more focused investigation of time-critical cognitive processes. Study designs also commonly separate periods of creative thought from response production to restrict the effect of response-related motor artifacts and to assess brain activity unique to the generation of creative ideas or solutions. We discuss the pros and cons of the various approaches with respect to the goal to increase reliability of neurophysiological measurements while maintaining valid assessments, and derive some recommendations for future research.
The solution to a problem might manifest itself as a burst of unexpected, unpredictable clarity. Such Eureka! events, or Insight moments, are among the most fascinating mysteries of human cognition, whose neurophysiological substrate seems to include a role for oscillatory activity within the α and γ bands in the right parietal and temporal brain regions. We tested this hypothesis on thirty-one healthy participants using transcranial Alternating Current Stimulation (tACS) to externally amplify α (10 Hz) and γ (40 Hz) activity in the right parietal and temporal lobes, respectively. During γ-tACS over the right temporal lobe, we observed an increase in accuracy on a verbal insight task. Furthermore, electroencephalography (EEG) data revealed an increase in γ spectral power over bilateral temporal lobes after stimulation. Additionally, resting-state functional MRI data acquired before the stimulation session suggested a correlation between behavioral response to right temporal lobe tACS and functional connectivity of bilateral temporal lobes, in line with the bilateral increase in γ band revealed by EEG. Overall, results suggest the possibility of enhancing the probability of generating Eureka! moments in humans by means of frequency-specific noninvasive brain stimulation.
Transcranial electrical stimulation (TES) uses constant (TDCS) or alternating currents (TACS) to modulate brain activity. Most TES studies apply low-intensity currents through scalp electrodes (≤2 mA) using bipolar electrode arrangements, producing weak electrical fields in the brain (<1 V/m). Low-intensity TES has been employed in humans to induce changes in task performance during or after stimulation. In analogy to focal transcranial magnetic stimulation, TES-induced behavioral effects have often been taken as evidence for a causal involvement of the brain region underlying one of the two stimulation electrodes, often referred to as the active electrode. Here, we critically review the utility of bipolar low-intensity TES to localize human brain function. We summarize physiological substrates that constitute peripheral targets for TES and may mediate subliminal or overtly perceived peripheral stimulation during TES. We argue that peripheral co-stimulation may contribute to the behavioral effects of TES and should be controlled for by “sham” TES. We discuss biophysical properties of TES, which need to be considered, if one wishes to make realistic assumptions about which brain regions were preferentially targeted by TES. Using results from electric field calculations, we evaluate the validity of different strategies that have been used for selective spatial targeting. Finally, we comment on the challenge of adjusting the dose of TES considering dose–response relationships between the weak tissue currents and the physiological effects in targeted cortical areas. These considerations call for caution when attributing behavioral effects during or after low-intensity TES studies to a specific brain region and may facilitate the selection of best practices for future TES studies.
Significance
“Taking a less-traveled path” is often considered an effective approach to creativity (i.e., creative thinking calls for a break from habitual thinking and associations), yet little is known about its underlying neural mechanism. In a series of four independent experiments involving electrophysiological and brain stimulation methods we provide evidence that this process is mediated by the right temporal alpha oscillations. Alpha oscillations are known to represent a process of active inhibition to suppress irrelevant information, such as inhibiting distractions during visual search. Through monitoring the brain’s electrical activity during different creativity tasks and by stimulating the right temporal brain region at the alpha frequency we show that a similar process of active inhibition is also key to creative thinking.
This article provides a brief summary of the history of transcranial methods for stimulating the human brain in conscious volunteers and reviews the methodology and physiology of transcranial magnetic stimulation and transcranial direct current stimulation. The former stimulates neural axons and generates action potentials and synaptic activity, whereas the latter polarises the membrane potential of neurones and changes their sensitivity to ongoing synaptic inputs. When coupled with brain imaging methods such as functional magnetic resonance imaging or electroencephalography, transcranial magnetic stimulation can be used to chart connectivity within the brain. In addition, because it induces artificial patterns of activity that interfere with ongoing information processing within a cortical area, it is frequently used in cognitive psychology to produce a short-lasting ‘virtual lesion’. Both transcranial magnetic stimulation and transcranial direct current stimulation can produce short-lasting changes in synaptic excitability and associated changes in behaviour that are presently the source of much research for their therapeutic potential.
This study aimed to determine the effect of expertise on the eye fixation-related potentials (EFRPs) during the aesthetic evaluation of images, independently in focal and ambient modes of visual processing. Focal and ambient modes were identified by averaging EFRP waveforms about the beginning of long eye fixations followed by short saccades and short fixations followed by long saccades, respectively. Thirty experts with formal training in visual arts and thirty-two non-experts freely viewed 150 figurative paintings presented for 20 s, each. After viewing the painting, the participant answered the question: “Is this painting beautiful?” Differences were found between the group of experts and non-experts due to the amplitude of EFRPs but only in focal mode, which is related to top-down, focused attention on the objects. Long fixations of experts had a higher amplitude of the parietal P2 recorded from right site than non-experts. In the group of experts, the frontal P2 was higher for long fixations on not beautiful paintings in comparison to long fixation on beautiful paintings. Moreover, in focal mode, there were higher occipital lambda response and N1-P2 complex for not beautiful than beautiful paintings. These results are discussed in the light of the results of studies on the effect of visual art expertise on event-related potentials (ERPs), ERP studies during aesthetic judgment task, and the knowledge of different modes of visual processing and EFRPs.
Neuroscientific research has revealed interconnected brain networks implicated in musical creativity, such as the executive control network, the default mode network, and premotor cortices. The present study employed brain stimulation to evaluate the role of the primary motor cortex (M1) in creative and technically fluent jazz piano improvisations. We implemented transcranial direct current stimulation (tDCS) to alter the neural activation patterns of the left hemispheric M1 whilst pianists performed improvisations with their right hand. Two groups of expert jazz pianists (n = 8 per group) performed five improvisations in each of two blocks. In Block 1, they improvised in the absence of brain stimulation. In Block 2, one group received inhibitory tDCS and the second group received excitatory tDCS while performing five new improvisations. Three independent expert-musicians judged the 160 performances on creativity and technical fluency using a 10-point Likert scale. As the M1 is involved in the acquisition and consolidation of motor skills and the control of hand orientation and velocity, we predicted that excitatory tDCS would increase the quality of improvisations relative to inhibitory tDCS. Indeed, improvisations under conditions of excitatory tDCS were rated as significantly more creative than those under conditions of inhibitory tDCS. A music analysis indicated that excitatory tDCS elicited improvisations with greater pitch range and number/variety of notes. Ratings of technical fluency did not differ significantly between tDCS groups. We discuss plausible mechanisms by which the M1 region contributes to musical creativity.
Group musical improvisation is thought to be akin to conversation, and therapeutically has been shown to be effective at improving communicativeness, sociability, creative expression, and overall psychological health. To understand these therapeutic effects, clarifying the nature of brain activity during improvisational cognition is important. Some insight regarding brain activity during improvisational music cognition has been gained via functional magnetic resonance imaging (fMRI) and electroencephalography (EEG). However, we have found no reports based on magnetoencephalography (MEG). With the present study, we aimed to demonstrate the feasibility of improvisational music performance experimentation in MEG. We designed a novel MEG-compatible keyboard, and used it with experienced musicians (N = 13) in a music performance paradigm to spectral-spatially differentiate spontaneous brain activity during mental imagery of improvisational music performance. Analyses of source activity revealed that mental imagery of improvisational music performance induced greater theta (5–7 Hz) activity in left temporal areas associated with rhythm production and communication, greater alpha (8–12 Hz) activity in left premotor and parietal areas associated with sensorimotor integration, and less beta (15–29 Hz) activity in right frontal areas associated with inhibition control. These findings support the notion that musical improvisation is conversational, and suggest that creation of novel auditory content is facilitated by a more internally-directed, disinhibited cognitive state.
Neural oscillations at the network level synchronize activity between regions and temporal scales. Transcranial alternating current stimulation (tACS), the delivery of low-amplitude electric current to the scalp, provides a tool for investigating the causal role of neural oscillations in cognition. The parameter space for tACS is vast and optimization is required in terms of temporal and spatial targeting. We review emerging techniques and suggest novel approaches that capitalize on the non-sinusoidal and transient nature of neural oscillations and leverage the flexibility provided by a customizable electrode montage and electrical waveform. The customizability and safety profile of tACS make it a promising tool for precision intervention in psychiatric illnesses.
Perceiving art is known to elicit motor cortex activation in an observer's brain. This motor activation has often been attributed to a covert approach response associated with the emotional valence of an art piece (emotional reaction hypothesis). However, recent accounts have proposed that aesthetic experiences could be grounded in the motor simulation of actions required to produce an art piece and of the sensorimotor states embedded in its subject (embodied aesthetic hypothesis). Here, we aimed to test these two hypotheses by assessing whether motor facilitation during artwork perception mirrors emotional or motor simulation processes. To this aim, we capitalized on single pulse transcranial magnetic stimulation revealing a two-stage motor coding of emotional body postures: an early, non-specific activation related to emotion processing and a later action-specific activation reflecting motor simulation. We asked art-naïve individuals to rate how much they liked a series of pointillist and brushstroke canvases; photographs of artistic gardens served as control natural stimuli. After an early (150 ms) or a later (300 ms) post-stimulus delay, motor evoked potentials were recorded from wrist-extensor and finger muscles that were more involved in brushstroke- and pointillist-like painting, respectively. Results showed that observing the two canvas styles did not elicit differential motor activation in the early time window for either muscle, not supporting the emotional reaction hypothesis. However, in support of the embodied aesthetic hypothesis, we found in the later time window greater motor activation responses to brushstroke than pointillist canvases for the wrist-extensor, but not for the finger muscle. Furthermore, this muscle-selective facilitation was associated with lower liking ratings of brushstroke canvases and with greater empathy dispositions. These findings support the claim that simulation of the painter's movements is crucial for aesthetic experience, by documenting a link between motor simulation, dispositional empathy, and subjective appreciation in artwork perception.
Trait anxiety has been shown to moderate transcranial direct current stimulation (tDCS) effects on some cognitive functions. Based on the attentional control theory (ACT), trait anxiety might be closely related to dysfunctional executive control and prefrontal activity. Importantly, executive and prefrontal functions are necessary for creativity. Critically, it is unknown whether trait anxiety moderates tDCS effects on creativity. To address this, thirty low-trait-anxious (LTA) and thirty-one high-trait-anxious (HTA) participants performed creativity tasks assessing divergent thinking (alternate uses task, AUT) and convergent thinking (compound remote associates test, CRAT), while receiving three types of tDCS (L-R+: left cathodal/right anodal; L+R-: reverse protocol; sham) over the bilateral dorsolateral prefrontal cortex (DLPFC). L+R- stimulation promoted superior performance on the AUT compared with the other two stimulations. Importantly, L+R- stimulation benefitted LTA but not HTA individuals. No significant main nor interactive effects were found on the CRAT. These results demonstrate that L+R- stimulation benefits divergent but not convergent thinking. Furthermore, divergent thinking is more sensitive to L+R- stimulation in the LTA group than in the HTA group. Based on the ACT, this is likely due to differential DLPFC activation between the groups. Future studies should consider trait anxiety when exploring tDCS effects on creativity.
The effects of online Transcranial Magnetic Stimulation (TMS) can qualitatively vary as a function of brain state. For example, TMS intensities which normally impair performance can have a facilitatory effect if the targeted neuronal representations are in a suppressed state. These phenomena have been explained in terms of the existence of distinct facilitatory and suppressive ranges as a function of TMS intensity which are shifted by changes in neural excitability. We tested this model by applying TMS at a low (60 % of phosphene threshold) or high (120 % of phosphene threshold) intensity during a priming paradigm. Our results show that state-dependent TMS effects vary qualitatively as a function of TMS intensity. Whereas the application of TMS at 120 % of participants’ phosphene threshold impaired performance on fully congruent trials (in effect, reducing the benefit of priming), TMS applied at a lower intensity (60 % of phosphene threshold), facilitated performance on congruent trials. These results demonstrate that behavioral effects of TMS reflect a nonlinear interaction between initial activation state and TMS intensity. They also provide support for the existence of facilitatory/suppressive ranges of TMS effects which shift when neural excitability changes.
It has been hypothesized that embodied mechanisms encompassing the simulation of actions, emotions and corporeal sensations contribute to aesthetic appreciation of art. In line with this, in this study, we assessed whether there is a relationship between the extent to which an artwork triggers motor resonance mechanisms and liking for the artwork. To this aim, we measured motor evoked potentials (MEPs) induced by TMS over M1 whilst participants viewed a series of paintings depicting either humans in static postures or performing dynamic actions, and paintings depicting static or dynamic non-human scenes. Following recording of MEPs, participants indicated how much they liked each painting and found the painting to be dynamic. Viewing of paintings depicting dynamic human actions was associated with a significant increase in MEPs size compared to baseline and to viewing of the other paintings. The more the painting conveyed the impression of a dynamic human action, the higher the MEPs amplitude and the more the artwork was liked. However, liking per se was not related to MEPs size. In fact, the positive relationship between MEPs size and preference for paintings depicting humans was entirely mediated by the perceived dynamism of the portrayed actions, and no positive relationship was observed between subjective preference for paintings depicting landscapes/objects and MEPs size. Overall, our data help shed light on the intriguing link between embodied resonance and aesthetic experience elicited by visual art, and show that characterization of motor cortical excitability may serve as a promising approach in neuroaesthetics.
Keywords: MEP; TMS; aesthetic appreciation; artworks; motor resonance; neuroaesthetics; paintings.
Significance
Studies have suggested a role for episodic memory in imagining future events and thinking creatively. Here, we tested the causal role played by episodic memory in future imagining and creative thinking by using fMRI-guided transcranial magnetic stimulation to disrupt neural activity in the hippocampus, a brain region involved in episodic memory. After transcranial magnetic stimulation, participants generated fewer episodic details when imagining future events and produced fewer creative ideas. fMRI analyses revealed that these behavioral reductions were linked to a reduction in hippocampal activity. Our findings have implications for brain targets and interventions to alleviate declines in memory, imagination, creativity, and other sorts of adaptive episodic functioning.
The perception of visual motion is dependent on a set of occipitotemporal regions that are readily accessible to neuromodulation. The current study tested if paired-pulse Transcranial Magnetic Stimulation (ppTMS) could modulate motion perception by stimulating the occipital cortex as participants viewed near-threshold motion dot stimuli. In this sham-controlled study, fifteen subjects completed two sessions. On the first visit, resting motor threshold (RMT) was assessed, and participants performed an adaptive direction discrimination task to determine individual motion sensitivity. During the second visit, subjects performed the task with three difficulty levels as TMS pulses were delivered 150 and 50 ms prior to motion stimulus onset at 120% RMT, under the logic that the cumulative inhibitory effect of these pulses would alter motion sensitivity. ppTMS was delivered at one of two locations: 3 cm dorsal and 5 cm lateral to inion (scalp-based coordinate), or at the site of peak activation for “motion” according to the NeuroSynth fMRI database (meta-analytic coordinate). Sham stimulation was delivered on one-third of trials by tilting the coil 90°. Analyses showed no significant active-versus-sham effects of ppTMS when stimulation was delivered to the meta-analytic (p = 0.15) or scalp-based coordinates (p = 0.17), which were separated by 29 mm on average. Active-versus-sham stimulation differences did not interact with either stimulation location (p = 0.12) or difficulty (p = 0.33). These findings fail to support the hypothesis that long-interval ppTMS recruits inhibitory processes in motion-sensitive cortex but must be considered within the limited parameters used in this design.
Among the brain regions involved in the aesthetic evaluation of paintings, the prefrontal cortex seems to play a pivotal role. In particular, consistent neuroimaging evidence indicates that activity in the dorsolateral prefrontal cortex (mainly in the left hemisphere) and in medial and orbital sectors of the prefrontal cortex is linked to viewing aesthetically pleasing images. In this study, we focused on the contribution of the medial prefrontal cortex (mPFC) in mediating aesthetic decisions about paintings. We found that enhancing excitability in this region via anodal tDCS led participants to judge paintings as more beautiful. Although significant, the effects were moderate, possibly due to the neutral affective value of the artworks we used, suggesting that activity in mPFC may be critically dependent on the affective impact of the paintings.
Visual aesthetic evaluations, which impact decision-making and well-being, recruit the ventral visual pathway, subcortical reward circuitry, and parts of the medial prefrontal cortex overlapping with the default-mode network (DMN). However, it is unknown whether these networks represent aesthetic appeal in a domain-general fashion, independent of domain-specific representations of stimulus content (artworks versus architecture or natural landscapes). Using a classification approach, we tested whether the DMN or ventral occipitotemporal cortex (VOT) contains a domain-general representation of aesthetic appeal. Classifiers were trained on multivoxel functional MRI response patterns collected while observers made aesthetic judgments about images from one aesthetic domain. Classifier performance (high vs. low aesthetic appeal) was then tested on response patterns from held-out trials from the same domain to derive a measure of domain-specific coding, or from a different domain to derive a measure of domain-general coding. Activity patterns in category-selective VOT contained a degree of domain-specific information about aesthetic appeal, but did not generalize across domains. Activity patterns from the DMN, however, were predictive of aesthetic appeal across domains. Importantly, the ability to predict aesthetic appeal varied systematically; predictions were better for observers who gave more extreme ratings to images subsequently labeled as “high” or “low.” These findings support a model of aesthetic appreciation whereby domain-specific representations of the content of visual experiences in VOT feed in to a “core” domain-general representation of visual aesthetic appeal in the DMN. Whole-brain “searchlight” analyses identified additional prefrontal regions containing information relevant for appreciation of cultural artifacts (artwork and architecture) but not landscapes.
Despite the increasing interest in the plasticity of aesthetic appreciation, we know comparatively little about the role of individuals' cultural (e.g. the appreciators' expertise) and of social emotional-cognitive (e.g. the social influence of people perceived as warm or competent) variables in modulating the appreciation process. In two experiments we investigated 1) whether people with different art-expertise are influenced differently by con-textual (i.e. stimuli primed as art) and social (i.e. stimuli rated as beautiful by art-critics) information and 2) whether acknowledging the judgment of a person perceived as warm or as competent has a different influence on individuals' aesthetic appreciation of art works. Warmth and competence are two social dimensions of fundamental importance for categorizing others as in-group or out-group (Fiske, Cuddy, Glick, & Xu, 2002). We found that insinuating that the observed works were pieces of art, highly appreciated by art critics, lead expert participants to judge the stimuli as more beautiful in comparison to when the very same stimuli were not preceded by any manipulation. Moreover, we found that both art-experts and non-experts rated the stimuli as more beautiful when they believed it to be highly appreciated by people perceived as warm vs people perceived as competent. These results provide novel information on the plasticity of aesthetics and pave the way to understanding how tastes and preferences in the domain of aesthetics can be influenced.
Background:
Creativity is the use of original ideas to accomplish something innovative. Previous research supports the notion that creativity is facilitated by an activation of the right and/or a deactivation of the left prefrontal cortex. In contrast, recent brain imaging studies suggest that creativity improves with left frontal activation.
Objective:
The present study was designed to further elucidate the neural basis of and ways to modulate creativity, based on the modulation of prefrontal cortical activity through the non-invasive brain stimulation technique transcranial direct current stimulation (tDCS).
Methods:
Ninety healthy University students performed three tasks on major aspects of creativity: conceptual expansion (Alternate Uses Task, AUT), associative thinking (Compound Remote Associate Task, CRA), and set shifting ability (Wisconsin Card Sorting Task, WCST). Simultaneously, they received cathodal stimulation of the left and anodal stimulation of the right inferior frontal gyrus (IFG), the reverse protocol, or sham stimulation.
Results:
The main pattern of results was a superior performance with bilateral left cathodal/right anodal stimulation, and an inferior performance in the reversed protocol compared to sham stimulation. As a potential underlying physiological mechanism, resting state EEG beta power, indicative of enhanced cortical activity, in the right frontal area increased with anodal stimulation and was associated with better performance.
Conclusion:
The findings provide new insights into ways of modulating creativity, whereby a deactivation of the left and an activation of the right prefrontal cortex with tDCS is associated with increased creativity. Potential future applications might include tDCS for patients with mental disorders and for healthy individuals in creative professions.
Creative thinking comprises two main components: divergent and convergent thinking. The Remote Associates Test (RAT) was designed to examine the ability to form associative elements into new combinations, however it is widely used as a general creativity measure, without sub-dividing it to its components. Our goal here was to explore the sub-components of the RAT, aiming to link them to the angular gyrus (AG) activation. The AG seems as a good candidate to host both aspects of the RAT, as neuroimaging studies observed deactivation in the AG while participants were engaged in creative tasks, however it also seems to play a role in arithmetic solution retrieval and automatic knowledge retrieval. Our objective was therefore to test whether transcranial direct current stimulation (tDCS) of the AG will influence creative and automatic performance in the RAT. In Experiment 1, in the creative group we administrated cathodal right AG stimulation in order to deactivate the AG aiming to improve divergent features of the RAT. In the automatic group, we administrated double anodal AG stimulation in order to improve convergent features of the RAT and included a control SHAM condition in each group. Experiment 2 activated the AG by stimulation and arithmetic training. We hypothesized that anodal stimulation of the AG will improve automatic convergent features as in Experiment 1. In addition, we expected the arithmetic training to improve the automatic score in the RAT. In Experiment 1, activation of the AG interrupted creative abilities and enhanced automatic abilities. Additionally, deactivation of the AG enhanced creative abilities reflecting divergent thinking. While in Experiment 2 both stimulation and arithmetic training resulted in higher automatic performance. We argue that the RAT measures automatic rather than creative abilities.
This chapter provides a broad introduction to computational models that inform and optimize tDCS for both clinical researchers and translational engineers. The first section introduces the rationale for modeling; the next two sections address technical features of modeling relevant to engineers (and to clinicians interested in the limitations of modeling); the following three sections address the use of modeling in clinical practice, and the final section illustrates the application of models in dose design through case studies. Computational “forward” models predict the flow of current throughout the head during tDCS, as with other brain stimulation techniques. Because the relationship between stimulation dose (defined as those electrode and waveform parameters controlled by the operator) and resulting brain current flow is complex and non-intuitive, computational forward models are essential to the rational design of stimulation protocols. Though model validation efforts are ongoing, these models already represent a standard tool to predict brain current flow and optimize tDCS dose, and so inform clinical practice and behavior research. Yet despite increased interest in tDCS modeling, as supported by the number of tDCS publications about or including a modeling component, access to modeling tools by clinicians remains highly limited. Ironically, much of the effort to enhance the relevance of modeling through increased sophistication (complexity) in fact hinders both reproduction and dissemination. This chapter therefore addresses not only the state-of-the-art in modeling techniques, but also how models can be immediately leveraged by researchers and clinicians.
Individual creativity, defined as the ability to achieve a production that is both original and appropriate, results in part from mental operations that may be related to the functioning of the brain. The challenge in this field of research is to understand what these operations are, and what cerebral networks underlie them. Although these questions are not fully elucidated, advances in the neuroscience of creativity have identified different brain networks that support distinct mechanisms of creativity. Recent data from cognitive and functional neuroimaging studies indicate that creativity is based on the interaction between associative thinking likely underpinned by the default mode network and cognitive control processes supported by control-related networks, including fronto-parietal networks. The study of brain-damaged patients made it possible to test this model and to establish a more causal link between the creative processes and these brain networks. The lesion approach has indeed shown the critical role of the default mode network and the left frontoparietal control network in the associative and control processes, respectively, and has identified crucial nodes in these networks. The few lesion studies carried out also suggest functional specialization of the prefrontal cortex for distinct creative processes. In this review, we integrate the results of lesion studies and noninvasive brain stimulation studies with the findings of recent functional imaging studies in healthy subjects to clarify our understanding of the brain mechanisms of creativity.
We review recent evidence for the hemispheric lateralization of attentional systems in the human brain. There is abundant anatomical, neuroimaging and neuromodulatory evidence for a relative lateralization towards the right hemisphere of some of the cortical networks supporting the attentional systems, especially those including the temporo-parietal junction and the ventro-lateral prefrontal cortex. Damage or disconnection of these right-lateralized nodes may produce severe deficits of spatial and nonspatial attention, as in visual neglect, or of inhibitory control. Finally, we examine the possibility that some of these hemispheric asymmetries are not exclusive to the human brain, but may also be instrumental in prioritizing information in non-human animals.
Neuroaesthetics is a rapidly developing interdisciplinary field of research that aims to understand the neural substrates of aesthetic experience: While understanding aesthetic experience has been an objective of philosophers for centuries, it has only more recently been embraced by neuroscientists. Recent work in neuroaesthetics has revealed that aesthetic experience with static visual art engages visual, reward and default-mode networks. Very little is known about the temporal dynamics of these networks during aesthetic appreciation. Previous behavioral and brain imaging research suggests that critical aspects of aesthetic experience have slow dynamics, taking more than a few seconds, making them amenable to study with fMRI. Here, we identified key aspects of the dynamics of aesthetic experience while viewing art for various durations. In the first few seconds following image onset, activity in the DMN (and high-level visual and reward regions) was greater for very pleasing images; in the DMN this activity counteracted a suppressive effect that grew longer and deeper with increasing image duration. In addition, for very pleasing art, the DMN response returned to baseline in a manner time-locked to image offset. Conversely, for non-pleasing art, the timing of this return to baseline was inconsistent. This differential response in the DMN may therefore reflect the internal dynamics of the participant's state: The participant disengages from art-related processing and returns to stimulus-independent thought. These dynamics suggest that the DMN tracks the internal state of a participant during aesthetic experience.
The investigation of creative cognition is rapidly advancing, driven by important methodological developments related to the modeling and scoring of creative performance, and stimulated by exciting contributions from cognitive neuroscience. Here, we argue that a deeper understanding of this complex cognitive capacity requires defining the role of its constituting neurocognitive functions including memory, attention, and cognitive control. The available evidence from cognitive and neuroscience research reveals several characteristic mechanisms of creative cognition including constructive memory processes to build novel representations, internally directed attention to support active imagination, and the relevance of executive control to implement goal-directed memory and attention processes. Together, these findings contribute toward an empirically substantiated neurocognitive framework of creative cognition.
Aesthetics has been regarded as a fundamental personal value. Most of the previous studies regarding aesthetic experience (AE) have focused on fine arts, rather than the everyday arts that are closely related to our everyday life. This study analysed the relationships among aesthetic life experience, expertise and different types of AE outcomes (aesthetic judgement and emotion) inspired by everyday designed products. The participants in this study were 115 college students, and an E‐prime program that included 120 pictures of designed products were employed to measure aesthetic judgement (beautiful, ordinary, or ugly) and aesthetic emotion (fearful, disgusting, neutral, or pleasure). The results revealed three major phenomena. (1) Two major types of AE outcomes are perceiving beauty with positive emotion and perceiving ugliness with negative emotion. (2) Although there are similar patterns for how aesthetic life experience and expertise influence personal tastes regarding beauty and aesthetic emotion, abundant expertise in designed products contributes more in differentiating emotion when viewing the beautiful designed products. (3) The consensus of the evaluation of ugliness is stronger than when evaluating beauty. In addition, a model of AE with regard to everyday designed products was proposed. The findings of this study shed light on the cultivation of aesthetic abilities and product design that could be utilised in education.
The human body is the most common object of pictorial representation in western art and its representations trigger a vast range of experiences from pain to pleasure. The goal of this study was to investigate brain activity triggered by paintings of male and female body images exemplifying conditions associated with pleasure or pain. Our findings show participant-general as well as gender specific brain activity for either the pain or the pleasure conditions. Although our participants were fully aware that they were viewing artworks, the inferior parietal lobule – known for its role in the perception of emotional body images – and the somatosensory cortex related to touch were selectively active for female body paintings in all participants in the pleasure conditions. As regards gender we observed that the sight of female bodies activated the subgenual anterior cingulate cortex in males, an area known to subserve autonomic arousal. In contrast, in females the sight of the male body activated reward and control related parts of the dorsal anterior cingulate cortex. This study supports the notion that some basic evolutionary processes operate when we view body images, also when they are cultural heritage paintings far removed from daily experience.
Computational models of transcranial current stimulation (tCS) derived from MRI predict the electric field distribution in individual brains with reasonable accuracy and should be used to guide the selection of optimal stimulation parameters. Some recent advances that support this claim are: free toolboxes to generate individual head models for electric field calculations, the validation of model predictions in comparison to in-vivo measurements, and new algorithms to optimize the electric field at the target with multi-electrode stimulation. Electrical impedance tomography may provide subject-specific estimates of the electric conductivity of the scalp and skull, thereby improving the accuracy of the electric field calculations. In the future, electric field models should be coupled with electrophysiological models to predict experimental outcomes.
The neuropsychological approach has been instrumental in delivering key insights that have enabled a clearer understanding of the human mind and its workings. Despite the promise of this approach and the unique perspective it affords, it has only been limitedly utilized when exploring creative cognition. This papers an overview of three methodologies – single case studies, case series investigations on neurological populations, and case series investigations on psychiatric populations – that have been employed within the neuropsychology of creativity and highlights some of the important revelations that each direction of study has delivered. In doing so, the aim is to make a case for the utility of the neuropsychological approach in allowing for a better understanding of the creative mind.
The book is organized around 4 sections. The first deals with the creativity and its neural basis (responsible editor Emmanuelle Volle). The second section concerns the neurophysiology of aesthetics (responsible editor Zoï Kapoula). It covers a large spectrum of different experimental approaches going from architecture, to process of architectural creation and issues of architectural impact on the gesture of the observer. Neurophysiological aspects such as space navigation, gesture, body posture control are involved in the experiments described as well as questions about terminology and valid methodology. The next chapter contains studies on music, mathematics and brain (responsible editor Moreno Andreatta). The final section deals with evolutionary aesthetics (responsible editor Julien Renoult).
When viewing a portrait, we are often captured by its expressivity, even if the emotion depicted is not immediately identifiable. If the neural mechanisms underlying emotion processing of real faces have been largely clarified, we still know little about the neural basis of evaluation of (emotional) expressivity in portraits. In this study, we aimed at assessing—by means of transcranial magnetic stimulation (TMS)—whether the right superior temporal sulcus (STS) and the right somatosensory cortex (SC), that are important in discriminating facial emotion expressions, are also causally involved in the evaluation of expressivity of portraits. We found that interfering via TMS with activity in (the face region of) right STS significantly reduced the extent to which portraits (but not other paintings depicting human figures with faces only in the background) were perceived as expressive, without, though, affecting their liking. In turn, interfering with activity of the right SC had no impact on evaluating either expressivity or liking of either paintings’ category. Our findings suggest that evaluation of emotional cues in artworks recruit (at least partially) the same neural mechanisms involved in processing genuine biological others. Moreover, they shed light on the neural basis of liking decisions in art by art-naïve people, supporting the view that aesthetic appreciation relies on a multitude of factors beyond emotional evaluation.
Historically, the brain bases of creativity have been of great interest to scholars and the public alike. However, recent technological innovations in the neurosciences, coupled with theoretical and methodological advances in creativity assessment, have enabled humans to gain unprecedented insights into the contributions of the brain to creative thought. This unique volume brings together contributions by the very best scholars to offer a comprehensive overview of cutting edge research on this important and fascinating topic. The chapters discuss creativity’s relationship with intelligence, motivation, psychopathology and pharmacology, as well as the contributions of general psychological processes to creativity, such as attention, memory, imagination, and language. This book also includes specific and novel approaches to understanding creativity involving musicians, polymaths, animal models, and psychedelic experiences. The chapters are meant to give the reader a solid grasp of the diversity of approaches currently at play in this active and rapidly growing field of inquiry.
Direct current stimulation is a neuromodulatory noninvasive brain stimulation tool, which was first introduced in animal and human experiments in the 1950s, and added to the standard arsenal of methods to alter brain physiology as well as psychological, motor, and behavioral processes and clinical symptoms in neurological and psychiatric diseases about 20 years ago. In contrast to other noninvasive brain stimulation tools, such as transcranial magnetic stimulation, it does not directly induce cerebral activity, but rather alters spontaneous brain activity and excitability by subthreshold modulation of neuronal membranes. Beyond acute effects on brain functions, specific protocols are suited to induce long-lasting alterations of cortical excitability and activity, which share features with long-term potentiation and depression. These neuroplastic processes are important foundations for various cognitive functions such as learning and memory formation and are pathologically altered in numerous neurological and psychiatric diseases. This explains the increasing interest to investigate transcranial direct current stimulation (tDCS) as a therapeutic tool. However, for tDCS to be used effectively, it is crucial to be informed about physiological mechanisms of action. These have been increasingly elucidated during the last years. This review gives an overview of the current knowledge available regarding physiological mechanisms of tDCS, spanning from acute regional effects, over neuroplastic effects to its impact on cerebral networks. Although knowledge about the physiological effects of tDCS is still not complete, this might help to guide applications on a scientifically sound foundation.