Influence of repressive coping style on cortical activation during encoding of angry faces.

BACKGROUND: Coping plays an important role for emotion regulation in threatening situations. The model of coping modes designates repression and sensitization as two independent coping styles. Repression consists of strategies that shield the individual from arousal. Sensitization indicates increased analysis of the environment in order to reduce uncertainty. According to the discontinuity hypothesis, repressors are sensitive to threat in the early stages of information processing. While repressors do not exhibit memory disturbances early on, they manifest weak memory for these stimuli later. This study investigates the discontinuity hypothesis using functional magnetic resonance imaging (fMRI). METHODS: Healthy volunteers (20 repressors and 20 sensitizers) were selected from a sample of 150 students on the basis of the Mainz Coping Inventory. During the fMRI experiment, subjects evaluated and memorized emotional and neutral faces. Subjects performed two sessions of face recognition: immediately after the fMRI session and three days later. RESULTS: Repressors exhibited greater activation of frontal, parietal and temporal areas during encoding of angry faces compared to sensitizers. There were no differences in recognition of facial emotions between groups neither immediately after exposure nor after three days. CONCLUSIONS: The fMRI findings suggest that repressors manifest an enhanced neural processing of directly threatening facial expression which confirms the assumption of hyper-responsivity to threatening information in repression in an early processing stage. A discrepancy was observed between high neural activation in encoding-relevant brain areas in response to angry faces in repressors and no advantage in subsequent memory for these faces compared to sensitizers.

Amygdala excitability to subliminally presented emotional faces distinguishes unipolar and bipolar depression: an fMRI and pattern classification study.

BACKGROUND: Bipolar disorder and Major depressive disorder are difficult to differentiate during depressive episodes, motivating research for differentiating neurobiological markers. Dysfunctional amygdala responsiveness during emotion processing has been implicated in both disorders, but the important rapid and automatic stages of emotion processing in the amygdala have so far never been investigated in bipolar patients. METHODS: fMRI data of 22 bipolar depressed patients (BD), 22 matched unipolar depressed patients (MDD), and 22 healthy controls (HC) were obtained during processing of subliminal sad, happy and neutral faces. Amygdala responsiveness was investigated using standard univariate analyses as well as pattern-recognition techniques to differentiate the two clinical groups. Furthermore, medication effects on amygdala responsiveness were explored. RESULTS: All subjects were unaware of the emotional faces. Univariate analysis revealed a significant group × emotion interaction within the left amygdala. Amygdala responsiveness to sad>neutral faces was increased in MDD relative to BD. In contrast, responsiveness to happy>neutral faces showed the opposite pattern, with higher amygdala activity in BD than in MDD. Most of the activation patterns in both clinical groups differed significantly from activation patterns of HC--and therefore represent abnormalities. Furthermore, pattern classification on amygdala activation to sad>happy faces yielded almost 80% accuracy differentiating MDD and BD patients. Medication had no significant effect on these findings. CONCLUSIONS: Distinct amygdala excitability during automatic stages of the processing of emotional faces may reflect differential pathophysiological processes in BD versus MDD depression, potentially representing diagnosis-specific neural markers mostly unaffected by current psychotropic medication.

Mood-congruent amygdala responses to subliminally presented facial expressions in major depression: associations with anhedonia.

BACKGROUND: Anhedonia has long been recognized as a key feature of major depressive disorders, but little is known about the association between hedonic symptoms and neurobiological processes in depressed patients. We investigated whether amygdala mood-congruent responses to emotional stimuli in depressed patients are correlated with anhedonic symptoms at automatic levels of processing. METHODS: We measured amygdala responsiveness to subliminally presented sad and happy facial expressions in depressed patients and matched healthy controls using functional magnetic resonance imaging. Amygdala responsiveness was compared between patients and healthy controls within a 2 (group) x 2 (emotion) design. In addition, we correlated patients' amygdala responsiveness to sad and happy facial stimuli with self-report questionnaire measures of anhedonia. RESULTS: We included 35 patients and 35 controls in our study. As in previous studies, we observed a strong emotion x group interaction in the bilateral amygdala: depressed patients showed greater amygdala responses to sad than happy faces, whereas healthy controls responded more strongly to happy than sad faces. The lack of automatic right amygdala responsiveness to happy faces in depressed patients was associated with higher physical anhedonia scores. LIMITATIONS: Almost all depressed patients were taking antidepressant medications. CONCLUSION: We replicated our previous finding of depressed patients showing automatic amygdala mood-congruent biases in terms of enhanced reactivity to negative emotional stimuli and reduced activity to positive emotional stimuli. The altered amygdala processing of positive stimuli in patients was associated with anhedonia scores. The results indicate that reduced amygdala responsiveness to positive stimuli may contribute to anhedonic symptoms due to reduced/inappropriate salience attribution to positive information at very early processing levels.

Tumor necrosis factor gene variation predicts hippocampus volume in healthy individuals.

BACKGROUND: Cytokines such as tumor necrosis factor (TNF) α have been implicated in neurodegeneration relevant to various neuropsychiatric disorders. Little is known about the genetic predisposition to neurodegenerative properties of cytokine genes on brain function and on hippocampus (HC) function in particular. In this study we investigate the neurodegenerative role of TNF polymorphisms on brain morphology in healthy individuals. METHODS: Voxel-based morphometry was used in a large sample of healthy individuals (n = 303) to analyze the associations between genetic variants of TNF (rs1800629; rs361525) and brain morphology (gray matter concentration). RESULTS: In a region of interest analysis of the HC, for rs1800629, we observed a strong genotype effect on bilateral HC gray matter concentration. Carriers of one or two A-alleles had significantly smaller volumes compared with GG-homozygotes. For rs361525, a similar effect was observed at almost the same location, with the A-allele resulting in smaller HC volumes compared with GG homozygotes. CONCLUSIONS: The findings suggest a neurodegenerative role of the A-alleles of the TNF single nucleotide polymorphisms rs1800629 (-308G/A) and rs361525 (-238G/A) on hippocampal volumes in healthy individuals. Future imaging studies on the role of these single nucleotide polymorphisms in psychiatric populations of diseases with neurodegenerative components are warranted.

High responsivity to threat during the initial stage of perception in repression: a 3 T fMRI study.

Repression designates coping strategies such as avoidance, or denial that aim to shield the organism from threatening stimuli. Derakshan et al. have proposed the vigilance-avoidance theory of repressive coping. It is assumed that repressors have an initial rapid vigilant response triggering physiological responses to threat stimuli. In the following second stage repressors manifest avoidant cognitive biases. Functional magnetic resonance imaging at 3T was used to study neural correlates of repressive coping during the first stages of perception of threat. Pictures of human faces bearing fearful, angry, happy and neutral expressions were briefly presented masked by neutral faces. Forty study participants (20 repressive and 20 sensitizing individuals) were selected from a sample of 150 female students on the basis of their scores on the Mainz Coping Inventory. Repressors exhibited stronger neural activation than sensitizers primarily in response to masked threatening faces (vs neutral baseline) in the frontal, parietal and temporal cortex as well as in the cingulate gyrus, basal ganglia and insula. There was no brain region in which sensitizers showed increased activation to emotion expression compared to repressors. The present results are in line with the vigilance-avoidance theory which predicts heightened automatic responsivity to threatening stimuli in repression.

Increased amygdala activation during automatic processing of facial emotion in schizophrenia.

Schizophrenia patients show abnormalities in the processing of facial emotion. The amygdala is a central part of a brain network that is involved in the perception of facial emotions. Previous functional neuroimaging studies on the perception of facial emotion in schizophrenia have focused almost exclusively on controlled processing. In the present study, we investigated the automatic responsivity of the amygdala to emotional faces in schizophrenia and its relationship to clinical symptomatology by applying an affective priming task. 3-T fMRI was utilized to examine amygdala responses to sad and happy faces masked by neutral faces in 12 schizophrenia patients and 12 healthy controls. The Positive and Negative Syndrome Scale (PANSS) was administered to assess current symptomatology. Schizophrenia patients exhibited greater automatic amygdala responses to sad and happy faces relative to controls. Amygdala responses to masked sad and happy expressions were positively correlated with the negative subscale of the PANSS. Schizophrenia patients appear to be characterized by amygdalar hyperresponsiveness to negative and positive facial expressions on an automatic processing level. Heightened automatic amygdala responsivity could be involved in the development and maintenance of negative symptoms in schizophrenia.

Attachment avoidance modulates neural response to masked facial emotion.

According to recent models of individual differences in attachment organization, a basic dimension of adult attachment is avoidance. Attachment-related avoidance corresponds to tendencies to withdraw from close relationships and to an unwillingness to rely on others. In the formation of attachment orientation during infancy facial emotional interaction plays a central role. There exists an inborn very rapid decoding capacity for facial emotional expression. In this study, functional magnetic resonance imaging was used to examine differences in automatic brain reactivity to facial emotions as a function of attachment avoidance in a sample of 51 healthy adults. Pictures of sad and happy faces (which are approach-related interpersonal signals) were presented masked by neutral faces. The Relationship Scales Questionnaire (RSQ) was used to assess the attachment avoidance. Masked sad faces activated the amygdala, the insula, occipito-temporal areas, and the somatosensory cortices. Independently from trait anxiety, depressivity, and detection performance, attachment avoidance was found to be inversely related to responses of the primary somatosensory cortex (BA 3) to masked sad faces. A low spontaneous responsivity of the primary somatosensory cortex to negative faces could be a correlate of the habitual unwillingness to deal with partners' distress and needs for proximity. The somatosensory cortices are known to be critically involved in the processes of emotional mimicry and simulation which have the potential to increase social affiliation. Our data are consistent with the idea that people who withdraw from close relationships respond spontaneously to a lesser extent to negative interpersonal emotional signals than securely attached individuals.

Threat sensitivity as assessed by automatic amygdala response to fearful faces predicts speed of visual search for facial expression.

It has been argued that the amygdala represents an integral component of a vigilance system that is primarily involved in the perception of ambiguous stimuli of biological relevance. The present investigation was conducted to examine the relationship between automatic amygdala responsivity to fearful faces which may be interpreted as an index of trait-like threat sensitivity and spatial processing characteristics of facial emotions. During 3T fMRI scanning, pictures of human faces bearing fearful, angry, and happy expressions were presented to 20 healthy volunteers using a backward masking procedure based on neutral facial expressions. Subsequently, a computer-based face-in-the-crowd task using schematic face stimuli was administered. The neural response of the (right) amygdala to masked fearful faces correlated consistently with response speed to negative and neutral faces. Neither amygdala activation during the masked presentation of angry faces nor amygdala activation during the presentation of happy faces was correlated with any of the response latencies in the face-in-the-crowd task. Our results suggest that amygdala responsivity to masked facial expression is differentially related to the general visual search speed for facial expression. Neurobiologically defined threat sensitivity seems to represent an important determinant of visual scanning behaviour.

Cognitive coping style modulates neural responses to emotional faces in healthy humans: a 3-T FMRI study.

Repression designates coping strategies that aim to shield the organism from distressing stimuli by disregarding their aversive characteristics. In contrast, sensitization comprises coping strategies that are employed to reduce situational uncertainty such as analyzing the environment. Functional magnetic resonance imaging was used to study neural correlates of coping styles during the perception of threatening and nonthreatening socially relevant information. Pictures of human faces bearing fearful (ambiguously threatening), angry (unambiguously threatening), happy (nonthreatening), and neutral expressions were presented masked and unmasked. Two groups of subjects were examined who were defined as consistent repressors versus consistent sensitizers with the Mainz Coping Inventory. Sensitizers tended to exhibit stronger neural responses in the amygdala to unmasked fearful faces compared with repressors. Overall, repressors were cortically more responsive to fearful (ambiguously threatening) and happy (nonthreatening) facial expressions than sensitizers, whereas sensitizers presented an enhanced responsivity to angry faces in several prefrontal areas, that is, unambiguously threatening expressions. Results from time series analyses suggest that sensitizers could exhibit less top-down cortical regulation of the amygdala than repressors in the processing of fearful faces. An increased responsivity of the amygdala to ambiguously threatening stimuli may represent a biological determinant of sensitizers' feelings of uncertainty.

Amygdala activation during masked presentation of emotional faces predicts conscious detection of threat-related faces.

It has been argued that critical functions of the human amygdala are to modulate the moment-to-moment vigilance level and to enhance the processing and the consolidation of memories of emotionally arousing material. In this functional magnetic resonance study, pictures of human faces bearing fearful, angry, and happy expressions were presented to nine healthy volunteers using a backward masking procedure based on neutral facial expression. Activation of the left and right amygdala in response to the masked fearful faces (compared to neutral faces) was significantly correlated with the number of fearful faces detected. In addition, right but not left amygdala activation in response to the masked angry faces was significantly related to the number of angry faces detected. The present findings underscore the role of the amygdala in the detection and consolidation of memory for marginally perceptible threatening facial expression.