Gregor Domes

Oxytocin and vasopressin in the human brain: social neuropeptides for translational medicine

The neuropeptides oxytocin (OXT) and arginine vasopressin (AVP) are evolutionarily highly conserved mediators in the regulation of complex social cognition and behaviour. Recent studies have investigated the effects of OXT and AVP on human social interaction, the genetic mechanisms of inter-individual variation in social neuropeptide signalling and the actions of OXT and AVP in the human brain as revealed by neuroimaging. These data have advanced our understanding of the mechanisms by which these neuropeptides contribute to human social behaviour. OXT and AVP are emerging as targets for novel treatment approaches — particularly in synergistic combination with psychotherapy — for mental disorders characterized by social dysfunction, such as autism, social anxiety disorder, borderline personality disorder and schizophrenia.

Oxytocin Attenuates Amygdala Responses to Emotional Faces Regardless of Valence

BACKGROUND Oxytocin is known to reduce anxiety and stress in social interactions as well as to modulate approach behavior. Recent studies suggest that the amygdala might be the primary neuronal basis for these effects. METHODS In a functional magnetic resonance imaging study using a double-blind, placebo-controlled within-subject design, we measured neural responses to fearful, angry, and happy facial expressions after intranasal application of 24 IU oxytocin compared with placebo. RESULTS Oxytocin reduced right-sided amygdala responses to all three face categories even when the emotional content of the presented face was not evaluated explicitly. Exploratory whole brain analysis revealed modulatory effects in prefrontal and temporal areas as well as in the brainstem. CONCLUSIONS Results suggest a modulatory role of oxytocin on amygdala responses to facial expressions irrespective of their valence. Reduction of amygdala activity to positive and negative stimuli might reflect reduced uncertainty about the predictive value of a social stimulus and thereby facilitates social approach behavior.

Oxytocin, vasopressin, and human social behavior.

There is substantial evidence from animal research indicating a key role of the neuropeptides oxytocin (OT) and arginine vasopressin (AVP) in the regulation of complex social cognition and behavior. As social interaction permeates the whole of human society, and the fundamental ability to form attachment is indispensable for social relationships, studies are beginning to dissect the roles of OT and AVP in human social behavior. New experimental paradigms and technologies in human research allow a more nuanced investigation of the molecular basis of social behavior. In addition, a better understanding of the neurobiology and neurogenetics of human social cognition and behavior has important implications for the current development of novel clinical approaches for mental disorders that are associated with social deficits (e.g., autism spectrum disorder, social anxiety disorder, and borderline personality disorder). This review focuses on our recent knowledge of the behavioral, endocrine, genetic, and neural effects of OT and AVP in humans and provides a synthesis of recent advances made in the effort to implicate the oxytocinergic system in the treatment of psychopathological states.

Effects of intranasal oxytocin on emotional face processing in women

The neuropeptide oxytocin (OXT) has previously been found to reduce amygdala reactivity to social and emotional stimuli in healthy men. The present study aimed to investigate the effect of intranasally administered OXT on brain activity in response to social emotional stimuli of varying valence in women. In a functional magnetic-resonance imaging study, sixteen women were presented with fearful, angry, happy and neutral facial expressions after a single dose of 24IU OXT or a placebo administration in a within-subject design. Group analysis revealed that the blood-oxygen-level-dependent (BOLD) signal was enhanced in the left amygdala, the fusiform gyrus and the superior temporal gyrus in response to fearful faces and in the inferior frontal gyrus in response to angry and happy faces following OXT treatment. This effect was independent of fixation pattern to specific sections of the facial stimuli as revealed by eye tracking and independent of basal plasma levels of OXT, estradiol, and progesterone. The results are at odds with the previously reported effects found in men. Future studies should include both sexes to determine a possible sexual dimorphism in the neural effects of OXT, considering gonadal steroids and OXT receptor affinity.

Neuropeptides and social behaviour: effects of oxytocin and vasopressin in humans

The fundamental ability to form attachment is indispensable for human social relationships. Impairments in social behaviour are associated with decreased quality of life and psychopathological states. In non-human mammals, the neuropeptides oxytocin (OXT) and arginine vasopressin (AVP) are key mediators of complex social behaviours, including attachment, social recognition and aggression. In particular, OXT reduces behavioural and neuroendocrine responses to social stress and seems both to enable animals to overcome their natural avoidance of proximity and to inhibit defensive behaviour, thereby facilitating approach behaviour. AVP has primarily been implicated in male-typical social behaviours, including aggression and pair-bond formation, and mediates anxiogenic effects. Initial studies in humans suggest behavioural, neural, and endocrine effects of both neuropeptides, similar to those found in animal studies. This review focuses on advances made to date in the effort to understand the role of OXT and AVP in human social behaviour. First, the literature on OXT and AVP and their involvement in social stress and anxiety, social cognition, social approach, and aggression is reviewed. Second, we discuss clinical implications for mental disorders that are associated with social deficits (e.g. autism spectrum disorder, borderline personality disorder). Finally, a model of the interactions of anxiety and stress, social approach behaviour, and the oxytocinergic system is presented, which integrates the novel approach of a psychobiological therapy in psychopathological states.

Emotion recognition in borderline personality disorder—A review of the literature.

Borderline personality disorder (BPD) is characterized by distinct impairments in emotion regulation, resulting in affective instability especially in the social context. It has been suggested that impaired social cognitive functioning such as impaired facial emotion recognition contributes to the social disturbances in BPD. In accordance with this notion, a number of behavioral studies have revealed a pattern of alterations in facial emotion recognition associated with BPD: subtle impairments in basic emotion recognition, a negativity or anger bias, and a heightened sensitivity to the detection of negative emotions. Furthermore, there is increasing evidence for structural and functional changes in the neural networks underlying affective dysregulation and emotional hyperreactivity in BPD. Merging these lines of evidence, we propose that emotional hyperreactivity interferes with the cognitive processes of facial emotion recognition, thereby contributing to the specific pattern of altered emotion recognition in BPD. Suggestions for future research and clinical implications are discussed.

The Neural Correlates of Sex Differences in Emotional Reactivity and Emotion Regulation

Sex differences in emotional responding have been repeatedly postulated but less consistently shown in empirical studies. Because emotional reactions are modulated by cognitive appraisal, sex differences in emotional responding might depend on differences in emotion regulation. In this study, we investigated sex differences in emotional reactivity and emotion regulation using a delayed cognitive reappraisal paradigm and measured whole‐brain BOLD signal in 17 men and 16 women. During fMRI, participants were instructed to increase, decrease, or maintain their emotional reactions evoked by negative pictures in terms of cognitive reappraisal. We analyzed BOLD responses to aversive compared to neutral pictures in the initial viewing phase and the effect of cognitive reappraisal in the subsequent regulation phase. Women showed enhanced amygdala responding to aversive stimuli in the initial viewing phase, together with increased activity in small clusters within the prefrontal cortex and the temporal cortex. During cognitively decreasing emotional reactions, women recruited parts of the orbitofrontal cortex, the anterior cingulate, and the dorsolateral prefrontal cortex to a lesser extent than men, while there was no sex effect on amygdala activity. In contrast, compared to women, men showed an increased recruitment of regulatory cortical areas during cognitively increasing initial emotional reactions, which was associated with an increase in amygdala activity. Clinical implications of these findings are discussed. Hum Brain Mapp, 2010.

Progression to Dementia in Clinical Subtypes of Mild Cognitive Impairment

Objective: To examine the outcome among patients diagnosed with different types of mild cognitive impairment (MCI). Patients: A follow-up examination (average follow-up period: 3.49 ± 2.2 years) was performed in 81 cognitively impaired, non-demented patients aged >55 years at baseline. Results: 8 of 32 patients with amnestic MCI (25%), 22 of 41 patients with multiple-domain MCI (54%), and 3 of 8 patients with single non-memory MCI (37.5%) progressed to dementia. The clinical type of MCI is significantly associated with the likelihood of conversion to dementia. Discussion: When the clinical syndrome of MCI evolves on a neurodegenerative basis, the multiple-domain type of MCI has a less favorable prognosis than the amnestic type and may represent a more advanced prodromal stage of dementia.

Effects of intranasal oxytocin on the neural basis of face processing in autism spectrum disorder

BACKGROUND Autism spectrum disorder (ASD) is associated with altered face processing and decreased activity in brain regions involved in face processing. The neuropeptide oxytocin has been shown to promote face processing and modulate brain activity in healthy adults. The present study examined the effects of oxytocin on the neural basis of face processing in adults with Asperger syndrome (AS). METHODS A group of 14 individuals with AS and a group of 14 neurotypical control participants performed a face-matching and a house-matching task during functional magnetic resonance imaging. The effects of a single dose of 24 IU intranasally administered oxytocin were tested in a randomized, placebo-controlled, within-subject, cross-over design. RESULTS Under placebo, the AS group showed decreased activity in the right amygdala, fusiform gyrus, and inferior occipital gyrus compared with the control group during face processing. After oxytocin treatment, right amygdala activity to facial stimuli increased in the AS group. CONCLUSIONS These findings indicate that oxytocin increases the saliency of social stimuli and in ASD and suggest that oxytocin might promote face processing and eye contact in individuals with ASD as prerequisites for neurotypical social interaction.

The influence of emotions on inhibitory functioning in borderline personality disorder

BACKGROUND Borderline personality disorder (BPD) is characterized by an emotionally unstable and impulsive cognitive and behavioral style. Inhibitory dysfunction has been hypothesized as playing a crucial role in BPD psychopathology. This study aimed to systematically investigate differential inhibitory functions in patients with BPD as compared to healthy controls, and to investigate their expected impairment in the context of aversive emotions by comparing performances in neuropsychological tasks that present both neutral and emotional material. METHOD Unmedicated female patients with BPD (n=28) were compared with age-matched healthy female controls (n=30) in the following tasks: the emotional Stroop test (inhibition of interference), directed forgetting (intentional, resource-dependent inhibition), and an emotional variant of the negative priming task (automatic, resource-independent inhibition). RESULTS In comparison with the controls, the BPD patients showed reduced inhibition of negative material in the directed forgetting task and in the negative priming task. No effect was found in the emotional Stroop test. Significant correlations with current affect as well as trait anxiety and anger (but not impulsiveness) were found in the BPD group specifically for negative stimuli, while no such correlations were found in the control group. In addition to inhibitory deficiencies, BPD patients had difficulties remembering positive words in the directed forgetting task. CONCLUSIONS Our data suggest that individuals with BPD have difficulties in actively suppressing irrelevant information when it is of an aversive nature. Inhibitory dysfunction appears to be closely related to state and trait variables of unstable affect, but not to self-reported impulsiveness.