MDMA enhances "mind reading” of positive emotions and impairs "mind reading” of negative emotions

Rationale: 3,4-Methylenedioxymethamphetamine (MDMA, ecstasy) increases sociability. The prosocial effects of MDMA may result from the release of the "social hormone” oxytocin and associated alterations in the processing of socioemotional stimuli. Materials and methods: We investigated the effects of MDMA (125mg) on the ability to infer the mental states of others from social cues of the eye region in the Reading the Mind in the Eyes Test. The study included 48 healthy volunteers (24 men, 24 women) and used a double-blind, placebo-controlled, within-subjects design. A choice reaction time test was used to exclude impairments in psychomotor function. We also measured circulating oxytocin and cortisol levels and subjective drug effects. Results: MDMA differentially affected mind reading depending on the emotional valence of the stimuli. MDMA enhanced the accuracy of mental state decoding for positive stimuli (e.g., friendly), impaired mind reading for negative stimuli (e.g., hostile), and had no effect on mind reading for neutral stimuli (e.g., reflective). MDMA did not affect psychomotor performance, increased circulating oxytocin and cortisol levels, and produced subjective prosocial effects, including feelings of being more open, talkative, and closer to others. Conclusions: The shift in the ability to correctly read socioemotional information toward stimuli associated with positive emotional valence, together with the prosocial feelings elicited by MDMA, may enhance social approach behavior and sociability when MDMA is used recreationally and facilitate therapeutic relationships in MDMA-assisted psychotherapeutic setting

The effect of oxytocin on attention to angry and happy faces in chronic depression

Background: Chronic depression is characterized by a high degree of early life trauma, psychosocial impairment, and deficits in social cognition. Undisturbed recognition and processing of facial emotions are basic prerequisites for smooth social interactions. Intranasal application of the neuropeptide oxytocin has been reported to enhance emotion recognition in neuropsychiatric disorders and healthy individuals. We therefore investigated whether oxytocin modulates attention to emotional faces in patients with chronic depression. Methods: In this double-blind, randomized, controlled study, 43 patients received a single dose of oxytocin or placebo nasal spray and were tested while fulfilling a facial dot probe task. We assessed reaction times to neutral probes presented at the location of one of two faces depicting happy, angry, or neutral expressions as a prime. Results: When comparing reaction times to the congruent (prime and probe at the same location) with incongruent presentation of facial emotions, neither the placebo nor oxytocin group showed an attentional preference for emotional facial expressions in terms of a threat bias. However, oxytocin treatment did reveal two specific effects: it generally reduced the allocation of attention towards angry facial expressions, and it increased sustained attention towards happy faces, specifically under conditions of heightened awareness, i.e. trials with longer primes. Conclusions: We investigated a heterogeneous group of medicated male and female patients. We conclude that oxytocin does modulate basic factors of facial emotion processing in chronic depression. Our findings encourage further investigations assessing the therapeutic potential of oxytocin in chronic depression

Enhancing precision in human neuroscience

Human neuroscience has always been pushing the boundary of what is measurable. During the last decade, concerns about statistical power and replicability – in science in general, but also specifically in human neuroscience – have fueled an extensive debate. One important insight from this discourse is the need for larger samples, which naturally increases statistical power. An alternative is to increase the precision of measurements, which is the focus of this review. This option is often overlooked, even though statistical power benefits from increasing precision as much as from increasing sample size. Nonetheless, precision has always been at the heart of good scientific practice in human neuroscience, with researchers relying on lab traditions or rules of thumb to ensure sufficient precision for their studies. In this review, we encourage a more systematic approach to precision. We start by introducing measurement precision and its importance for well-powered studies in human neuroscience. Then, determinants for precision in a range of neuroscientific methods (MRI, M/EEG, EDA, Eye-Tracking, and Endocrinology) are elaborated. We end by discussing how a more systematic evaluation of precision and the application of respective insights can lead to an increase in reproducibility in human neuroscience

Oxytocin and the social brain: Neural mechanisms and perspectives in human research

The present paper summarizes functional imaging studies investigating the effects of intranasal oxytocin (OT) on brain responses to social stimuli. We aim to integrate previous research, point to unresolved issues and highlight perspectives for future studies. The studies so far have focused on identifying neural circuits underlying social information processing which are particularly sensitive to modulations by exogenous OT. Most consistently, stimulus-related responses of the amygdala and associated areas within the prefrontal and temporal cortices have been found to be modulated by OT administration. However, there are a number of unresolved issues related to the possible role of sex differences and hormonal status, genetic variability, and individual differences in socio-cognitive functioning. Future studies focusing on these open questions are expected to contribute to a more nuanced understanding of the role of the central OT system in humans and may provide the basis for novel treatment approaches for mental disorders characterized by social deficits

Oxytocin changes behavior and spatio-temporal brain dynamics underlying inter-group conflict in humans

Inter-group conflicts drive human discrimination, mass migration, and violence, but their psychobiological mechanisms remain largely unknown. Here, we investigated whether the neuropeptide oxytocin modulates behavior and spatio-temporal brain dynamics in naturalistic inter-group conflict. Eighty-six male members of natural rival social groups received either oxytocin or placebo intranasally. In a decision-making paradigm involving real monetary stakes, participants could sacrifice their own resources to modulate the monetary gains and losses of in- and out-group members. Oxytocin eliminated the reduction in out-group gains – particularly in individuals with low emotional empathy, whereas those given placebo exhibited this negative social behavior. Our spatio-temporal analysis of event-related potentials elicited by outcome valuation revealed that oxytocin replaced a neurophysiological process associated with the negative valuation of out-group gains via a process associated with positive valuation between 200-500ms after outcome presentation. Oxytocin thus seems to modulate inter-group behavior in humans via a specific alteration of valuation-related brain dynamics

As time goes by: Oxytocin influences the subjective perception of time in a social context

Time perception depends on an event’s emotional relevance to the beholder; a subjective time dilation effect is associated with self-relevant, emotionally salient stimuli. Previous studies have revealed that oxytocin modulates the salience of social stimuli and attention to social cues. However, whether the oxytocin system is involved in human subjective time perception is unknown. The aim of the present study was to investigate whether increased oxytocin levels would induce a time dilation effect for self-relevant, positive social cues. In a double-blind, placebo-controlled, between-subject design, heterosexual men were administered intranasal oxytocin or placebo. After about 50 min, participants completed a time-bisection task in which they estimated lengths of exposure to happy female faces (self-relevant positive stimuli, based on sexual orientation), emotionally neutral and negative female faces (control), and happy, neutral, and negative male faces (control). Oxytocin induced a subjective time dilation effect for happy female faces and a time compression effect for happy male faces. Our results provide evidence that oxytocin influences time perception, a primary form of human subjectivity

Oxytocin attenuates neural reactivity to masked threat cues from the eyes

The neuropeptide oxytocin has recently been shown to modulate covert attention shifts to emotional face cues and to improve discrimination of masked facial emotions. These results suggest that oxytocin modulates facial emotion processing at early perceptual stages prior to full evaluation of the emotional expression. Here, we used functional magnetic resonance imaging to examine whether oxytocin alters neural responses to backwardly masked angry and happy faces while controlling for attention to the eye vs the mouth region. Intranasal oxytocin administration reduced amygdala reactivity to masked emotions when attending to salient facial features, ie, the eyes of angry faces and the mouth of happy faces. In addition, oxytocin decreased neural responses within the fusiform gyrus and brain stem areas, as well as functional coupling between the amygdala and the fusiform gyrus specifically for threat cues from the eyes. Effects of oxytocin on brain activity were not attributable to differences in behavioral performance, as oxytocin had no impact on mere emotion detection. Our results suggest that oxytocin attenuates neural correlates of early arousal by threat signals from the eye region. As reduced threat sensitivity may increase the likelihood of engaging in social interactions, our findings may have important implications for clinical states of social anxiety