Elevated response of human amygdala to neutral stimuli in mild post traumatic stress disorder: Neural correlates of generalized emotional response

Article (PDF Available)inNeuroscience 168(3):670-9 · April 2010with140 Reads
DOI: 10.1016/j.neuroscience.2010.04.024 · Source: PubMed
Previous evidence from functional magnetic resonance imaging (fMRI) studies has shown that amygdala responses to emotionally neutral pictures are exaggerated at a group level in patients with severe post-traumatic stress disorder (PTSD) [Hendler T, Rotshtein P, Yeshurun Y, Weizmann T, Kahn I, Ben-Bashat D, Malach R, Bleich A (2003) Neuroimage 19(3):587-600]. The present fMRI study tested the hypothesis that amygdala responses are elevated not only in response to negative pictures but also to neutral pictures as a function of disease severity in patients with mild symptoms and in subjects who did not develop symptoms. To this end, fMRI scans were performed in 10 patients with mild PTSD and 10 healthy controls (both victims of a bank robbery), during the execution of a visuo-attentional task in which they were asked to observe emotionally negative or neutral pictures. Control subjects showed enhanced amygdala responses to emotionally negative stimuli compared to neutral stimuli. On the contrary, PTSD patients were characterized by high amygdala responses to both neutral and emotional pictures, with no statistically significant difference between the two classes of stimuli. In the entire group, we found correlations among the severity of the PTSD symptoms, task performance, and amygdala activation during the processing of neutral stimuli. Results of this study suggest that amygdala responses and the selectivity of the emotional response to neutral stimuli are elevated as a function of disease severity in PTSD patients with mild symptoms.

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Available from: Claudia Catani, Apr 07, 2014
    • "A pertinent question concerns whether the neuro-functional alterations associated with trauma-exposure and post-traumatic stress reflects general alterations in activation for processing of negative or threatening emotional material, or if alterations are specifically connected to trauma-related material. The results have been inconsistent with some studies demonstrating neurofunctional alterations specifically connected to trauma-related or threatening material (Rauch et al., 1996; Liberzon et al., 1999; Hendler et al., 2003; Shin et al., 2004; Protopopescu et al., 2005), while other studies have reported general alterations in activation irrespective of valence or trauma relevance (Hendler et al., 2003; Brunetti et al., 2010). The majority of studies on neuro-functional patterns in the aftermath of trauma have focused on PTSD, and less attention has been directed toward the effects of trauma-exposure per se. "
    [Show abstract] [Hide abstract] ABSTRACT: Most studies of neuro-functional patterns in trauma-exposed individuals have been conducted considerable time after the traumatic event. Hence little is known about neuro-functional processing shortly after trauma-exposure. We investigated brain activity patterns in response to trauma reminders as well as neutral and negative stimuli in individuals who had recently (within 3 weeks) been involved in a road traffic accident (RTA). Twenty-three RTA survivors and 17 non-trauma-exposed healthy controls (HCs) underwent functional MRI while viewing Trauma-specific, Negative, and Neutral pictures. Data were analyzed from four a priori regions of interest, including bilateral amygdala, subcallosal cortex, and medial prefrontal cortex. In addition, we performed a whole brain analysis and functional connectivity analysis during stimulus presentation. For both groups, Negative stimuli elicited more activity in the amygdala bilaterally than did Neutral and Trauma-specific stimuli. The whole brain analysis revealed higher activation in sensory processing related areas (bilateral occipital and temporal cortices and thalamus) as well as frontal and superior parietal areas, for the RTA group compared to HC, for Trauma-specific stimuli contrasted with Neutral stimuli. We also observed higher functional connectivity for Trauma-specific stimuli, between bilateral amygdala and somatosensory areas, for the RTA group compared to controls, when contrasted with Neutral stimuli. We argue that these results might indicate an attentional sensory processing bias toward Trauma-specific stimuli for trauma exposed individuals, a result in line with findings from the post-traumatic stress disorder literature.
    Full-text · Article · Aug 2016
    • "Included studies contrasted a traumatic or negative emotional condition with a resting baseline, positive condition, or neutral condition, conducted betweengroup analyses using subtraction methodology, and reported between-group peak activation coordinates in standard space. For relevant articles that did not report whole-brain results, the authors were contacted to request activation coordinates [6,10]. Case studies were excluded [39,40] as well as studies examining PTSD and co-morbidity with other disorders, although an exception was made for major depressive disorder (MDD) because of its high co-morbidity with PTSD [13]. "
    Dataset · Jul 2016 · Journal of Psychiatric Research
    • "The lack of differentiation in N170 peak amplitude responses for non-conscious Angry relative to Happy faces for the subgroups of childhood interpersonal trauma or adult trauma-exposed healthy adults is however broadly in line with Felmingham et al.'s (2003) report of reduced differences in posterior early negative ERP amplitude responses to conscious Angry and Neutral faces in a PTSD group compared to controls. It could also be considered to be consistent with other studies using early ERP or functional MRI indices of neural activation which have found greater responses to facial stimuli regardless of emotion expression (Brunetti et al., 2010; Eldar et al., 2010; Steuwe et al., 2014) and which have been interpreted as reflecting a generalised heightened " alert " or vigilance state in PTSD. Alternatively, reduced N170 peak amplitude differences between non-conscious Angry and Happy faces could potentially reflect heightened responsivity to both positive and negativevalenced but high arousal relative to neutral emotion stimuli in trauma-exposed individuals (Killgore et al., 2014). "
    [Show abstract] [Hide abstract] ABSTRACT: Enhanced threat-related processing is associated with both elevated anxiety and childhood exposure to trauma. Given the paucity of evidence regarding the effects of childhood and adult trauma exposure on subsequent psychophysiological processes in the absence of psychopathology, we investigated the relative impacts of childhood interpersonal and non-interpersonal trauma, as well as adult trauma exposure on neural processing of threat in healthy adults. We measured peak amplitudes of the N170 face-sensitive visual ERP component response to non-conscious and conscious Angry (threat) versus Happy (non-threat, positive) and Neutral (non-threat baseline) faces at temporo-occipital sites (right-T6; left-T5) in 489 psychiatrically asymptomatic adults (aged 18-70 years, 54% women, 94% right-handed). N170 peak amplitude differences between Angry vs Happy or Neutral faces were calculated and subjected to hierarchical multiple regression analysis, with trauma types (childhood interpersonal, childhood non-interpersonal and adult trauma) entered as predictors of interest. After controlling for sociodemographic and health factors, N170 peak amplitudes for non-conscious Angry vs Happy faces were inversely associated with childhood interpersonal trauma at T6 and adult trauma exposure at T5. Post-hoc repeated measures ANOVA indicated that unlike adults without trauma exposure, trauma-exposed adults failed to show significantly reduced N170 responses to Happy relative to Angry faces during non-conscious processing. This suggests that childhood interpersonal and adult trauma exposure are associated with a failure to differentiate between non-threat or positive and threat-related emotion cues. This is consistent with generalised hypervigilance seen in PTSD, and suggests trauma exposure is associated with a generalized heightened responsivity to non-conscious non-threat or positive as well as threat-related emotion cues in psychiatrically healthy adults.
    Article · Mar 2016
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