Ihre Suche

Aversive social learning experiences might play a significant role in the aetiology of social anxiety disorder. Therefore, we investigated emotional learning and unlearning processes in healthy humans using a social conditioning paradigm. Forty-nine healthy subjects participated in a 2-day fMRI differential conditioning protocol. Acquisition and extinction were conducted on Day 1 and extinction recall on Day 2. BOLD responses, ratings and skin conductance responses were collected. Our data indicate successful conditioning and extinction on the neural and subjective level. As a main result, we observed a positive correlation of social anxiety and conditioning responses on the subjective level (valence and fear) as well as on the neural level with significant CS(+)/CS(-) differentiation in the left amygdala and the left hippocampus. Further, significant CS(+)/CS(-) differentiation in the left amygdala was found during extinction and was associated with lower scores in social anxiety. During extinction recall, we found a tendentially negative correlation of social anxiety and CS(+)/CS(-) differentiation in the vmPFC. In sum, we were able to show that social anxiety is related to conditionability with socially threatening stimuli. This could point to an important aspect in the aetiology of social anxiety disorder.

BACKGROUND: The underlying neurobiological mechanisms that account for the onset and maintenance of binge-eating disorder (BED) are not sufficiently understood. This functional magnetic resonance imaging (fMRI) study explored the neural correlates of visually induced food reward and loathing. METHOD: Sixty-seven female participants assigned to one of four groups (overweight BED patients, overweight healthy control subjects, normal-weight healthy control subjects, and normal-weight patients with bulimia nervosa) participated in the experiment. After an overnight fast, the participants' brain activation was recorded during each of the following three conditions: visual exposure to high-caloric food, to disgust-inducing pictures, and to affectively neutral pictures. After the fMRI experiment, the participants rated the affective value of the pictures. RESULTS: Each of the groups experienced the food pictures as very pleasant. Relative to the neutral pictures, the visual food stimuli provoked increased activation in the orbitofrontal cortex (OFC), anterior cingulate cortex (ACC), and insula across all participants. The BED patients reported enhanced reward sensitivity and showed stronger medial OFC responses while viewing food pictures than all other groups. The bulimic patients displayed greater arousal, ACC activation, and insula activation than the other groups. Neural responses to the disgust-inducing pictures as well as trait disgust did not differ between the groups. CONCLUSIONS: This study provides first evidence of differential brain activation to visual food stimuli in patients suffering from BED and bulimia nervosa.

Cognitive reappraisal and expressive suppression, two major emotion regulation strategies, are differentially related to emotional well-being. The aim of this study was to test the association of individual differences in these two emotion regulation strategies with gray matter volume of brain regions that have been shown to be involved in the regulation of emotions. Based on high-resolution magnetic resonance images of 96 young adults voxel-based morphometry was used to analyze the gray matter volumes of the a priori regions of interest, including amygdala, insula, dorsal anterior cingulate and paracingulate cortex, medial and lateral prefrontal cortex (PFC) and their association with cognitive reappraisal and expressive suppression usage as well as neuroticism. A positive association of cognitive reappraisal with right and tendentially left amygdala volume and of neuroticism with left amygdala volume (marginally significant) was found. Expressive suppression was related to dorsal anterior cingulate/paracingulate cortex and medial PFC gray matter volume. The results of this study emphasize the important role of the amygdala in individual differences in cognitive reappraisal usage as well as neuroticism. Additionally, the association of expressive suppression usage with larger volumes of the medial PFC and dorsal anterior/paracingulate cortex underpins the role of these regions in regulating emotion-expressive behavior.

Neurofunctional mechanisms underlying cognitive behavior therapy (CBT) are still not clearly understood. This functional magnetic resonance imaging (fMRI) study focused on changes in brain activation as a result of one-session CBT in patients suffering from spider phobia. Twenty-six female spider phobics and 25 non-phobic subjects were presented with spider pictures, generally disgust-inducing, generally fear-inducing and affectively neutral scenes in an initial fMRI session. Afterwards, the patients were randomly assigned to either a therapy group (TG) or a waiting list group (WG). The scans were repeated one week after the treatment or after a one-week waiting period. Relative to the non-phobic participants, the patients displayed increased activation in the amygdala and the fusiform gyrus as well as decreased activation in the medial orbitofrontal cortex (OFC) during the first exposure. The therapy effect consisted of increased medial OFC activity in the TG relative to the WG. Further, therapy-related reductions in experienced somatic anxiety symptoms were positively correlated with activation decreases in the amygdala and the insula. We conclude that successful treatment of spider phobia is primarily accompanied by functional changes of the medial OFC. This brain region is crucial for the self-regulation of emotions and the relearning of stimulus-reinforcement associations.

BACKGROUND: Extinction learning is proposed to be one key mechanism of action underlying exposure-based cognitive-behavioral therapy (CBT) in specific phobia. Beyond that, cognitive reappraisal, one important strategy to regulate negative emotions, is a crucial component of CBT interventions, but has been disregarded in previous studies investigating neural change processes in specific phobia. The aim of this study was to investigate the association of individual differences in habitual/dispositional cognitive reappraisal usage and the time course of brain activation during phobic stimulation in specific phobia. METHODS: Dental phobic patients and healthy control subjects participated in a functional magnetic resonance imaging (fMRI) study whilst being confronted with phobic, disgust, fear and neutral pictures. Individual differences in cognitive reappraisal usage were assessed via a self-report questionnaire and correlated with activation decreases over the course of time. RESULTS: Phobic individuals with higher dispositional cognitive reappraisal scores showed a more pronounced activation decline in the right dorsomedial prefrontal cortex (dmPFC) which might be associated with a diminution of explicit cognitive emotion regulation over the course of time. Less decrease of activation in the right ventromedial prefrontal cortex (vmPFC) and the lateral orbitofrontal cortex (lOFC) over time in subjects with higher cognitive reappraisal scores might be related to a stronger automatic regulation of emotions or even emotional relearning. Additionally, phobic subjects compared with healthy controls showed a stronger habituation of the left dmPFC over the course of symptom provocation. CONCLUSIONS: The results of this study show for the first time that individual differences in cognitive reappraisal usage are associated with the time course of brain activation during symptom provocation in specific phobia. Additionally, the present study gives first indications for the importance of considering individual differences in cognitive reappraisal usage in the treatment of specific phobia.

Phobic responses are strong emotional reactions towards phobic objects, which can be described as a deficit in the automatic regulation of emotions. Difficulties in the voluntary cognitive control of these emotions suggest a further phobia-specific deficit in effortful emotion regulation mechanisms. The actual study is based on this emotion regulation conceptualization of specific phobias. The aim is to investigate the neural correlates of these two emotion regulation deficits in spider phobics. Sixteen spider phobic females participated in a functional magnetic resonance imaging (fMRI) study in which they were asked to voluntarily up- and down-regulate their emotions elicited by spider and generally aversive pictures with a reappraisal strategy. In line with the hypothesis concerning an automatic emotion regulation deficit, increased activity in the insula and reduced activity in the ventromedial prefrontal cortex was observed. Furthermore, phobia-specific effortful regulation within phobics was associated with altered activity in medial prefrontal cortex areas. Altogether, these results suggest that spider phobic subjects are indeed characterized by a deficit in the automatic as well as the effortful regulation of emotions elicited by phobic compared with aversive stimuli. These two forms of phobic emotion regulation deficits are associated with altered activity in different medial prefrontal cortex subregions.

We examined the effects of symptom induction on neural activation in blood-injection-injury (BII) phobia. Nine phobic and 10 non-phobic subjects participated in an fMRI study in which they were presented with disorder-relevant, generally disgust-inducing, generally fear-evoking and neutral pictures. We observed diminished medial prefrontal cortex (MPFC) activity in patients compared to controls for phobia-relevant and disgust-inducing pictures. The MPFC has been shown to be critically involved in the automatic and effortful cognitive regulation of emotions. Therefore, the results might reflect reduced cognitive control of emotions in BII phobics during the experience of phobic symptoms as well as during states of disgust. The latter response component might be a result of the elevated disgust sensitivity of BII phobics.

Findings from several functional magnetic resonance imaging (fMRI) studies implicate the existence of a distinct neural disgust substrate, whereas others support the idea of distributed and integrative brain systems involved in emotional processing. In the present fMRI experiment 12 healthy females viewed pictures from four emotion categories. Two categories were disgust-relevant and depicted contamination or mutilation. The other scenes showed attacks (fear) or were affectively neutral. The two types of disgust elicitors received comparable ratings for disgust, fear and arousal. Both were associated with activation of the occipitotemporal cortex, the amygdala, and the orbitofrontal cortex; insula activity was nonsignificant in the two disgust conditions. Mutilation scenes induced greater inferior parietal activity than contamination scenes, which might mirror their greater capacity to capture attention. Our results are in disagreement with the idea of selective disgust processing at the insula. They point to a network of brain regions involved in the decoding of stimulus salience and the regulation of attention.

INTRODUCTION: Few studies so far have directly compared the neural processing of visual sexual stimuli in men and women. Also, most of these studies only compared sexual with neutral stimuli, making it difficult to disentangle sexual stimulus processing from general emotional processing. AIM: The current study aimed to explore gender commonalities and differences in neural activity associated with the processing of visual sexual stimuli in a large sample of 50 men and 50 women. In order to disentangle effects of sexual processing from those of general emotional processing, we employed sexual, neutral, positive, and negative emotional pictures. METHODS: Subjects passively viewed sexual, neutral, positive, and negative emotional pictures during a functional magnetic resonance imaging (fMRI) session. Pictures were presented in 24 blocks of five pictures each. Every block was rated immediately after its presentation with respect to valence, arousal, and sexual arousal. MAIN OUTCOME MEASURES: Blood oxygen level dependent responses measured by fMRI and subjective ratings. RESULTS: fMRI analysis revealed a distributed network for the neural processing of sexual stimuli comprising the hypothalamus, the nucleus accumbens, as well as orbitofrontal, occipital, and parietal areas. This network could be identified (i) for both men and women, with men showing overall stronger activations than women and (ii) independent of general emotional arousal or valence effects. CONCLUSION: Our data speak in favor of a common neural network associated with the processing of visual sexual stimuli in men and women. Apart from the observed gender commonalities, overall stronger responses in men were observed that might indicate stronger sexual responsivity in men.

Fear acquisition and extinction are crucial mechanisms in the etiology and maintenance of anxiety disorders. Moreover, they might play a pivotal role in conveying the influence of genetic and environmental factors on the development of a (more or less) stronger proneness for, or resilience against psychopathology. There are only few insights in the neurobiology of genetically and environmentally based individual differences in fear learning and extinction. In this functional magnetic resonance imaging study, 74 healthy subjects were investigated. These were invited according to 5-HTTLPR/rs25531 (S+ vs. L(A)L(A); triallelic classification) and TPH2 (G(-703)T) (T+ vs. T-) genotype. The aim was to investigate the influence of genetic factors and traumatic life events on skin conductance responses (SCRs) and neural responses (amygdala, insula, dorsal anterior cingulate cortex (dACC) and ventromedial prefrontal cortex (vmPFC)) during acquisition and extinction learning in a differential fear conditioning paradigm. Fear acquisition was characterized by stronger late conditioned and unconditioned responses in the right insula in 5-HTTLPR S-allele carriers. During extinction traumatic life events were associated with reduced amygdala activation in S-allele carriers vs. non-carriers. Beyond that, T-allele carriers of the TPH2 (G(-703)T) polymorphism with a higher number of traumatic life events showed enhanced responsiveness in the amygdala during acquisition and in the vmPFC during extinction learning compared with non-carriers. Finally, a combined effect of the two polymorphisms with higher responses in S- and T-allele carriers was found in the dACC during extinction. The results indicate an increased expression of conditioned, but also unconditioned fear responses in the insula in 5-HTTLPR S-allele carriers. A combined effect of the two polymorphisms on dACC activation during extinction might be associated with prolonged fear expression. Gene-by-environment interactions in amygdala and vmPFC activation may reflect a neural endophenotype translating genetic and adverse environmental influences into vulnerability for or resilience against developing affective psychopathology.