Biology subjects

Stoffel-Wagner, B.

Publications and source records attributed to Stoffel-Wagner, B..

3 recordsLinked to original sources

bioRxiv2021

Estradiol and oxytocin modulate sex differences in hippocampal reactivity and episodic memory

Considerable evidence supports sex differences in episodic memory, which may translate to heightened vulnerability to stress- and trauma-related disorders in women. The hormones estradiol and oxytocin both affect episodic memory, but possible underlying hormonal interactions have not been systemically tested in humans. To this end, healthy women (n = 111) and men (n = 115) received estradiol gel (2 mg) or placebo before the administration of intranasal oxytocin (24 IU) or placebo in a randomized, placebo-controlled, parallel-group functional magnetic resonance imaging (fMRI) study. In the fMRI session, participants viewed positive, neutral, and negative scenes. A surprise recognition task was conducted three days later. Under placebo, women showed a significantly better recognition memory and increased hippocampal responses to subsequently remembered items independent of the emotional valence compared to men. The separate treatments with either hormone significantly diminished this mnemonic sex difference and reversed the hippocampal activation pattern. However, the combined treatments led to a memory performance comparable to that of the placebo group. Collectively, the results suggest that both hormones play a crucial role in modulating sex differences in episodic memory. Furthermore, possible antagonistic interactions between estradiol and oxytocin could explain previously observed opposing hormonal effects in women and men.

neuroscience↗

bioRxiv2021

Lonely in the dark: trauma memory and sex-specific dysregulation of amygdala reactivity to fear signals

Loneliness exacerbates psychological distress and increases the risk of psychopathology after trauma exposure. The prevalence of trauma-associated disorders varies substantially between sexes, and accumulating evidence indicates sex-specific effects of loneliness. However, it is still unclear whether a lack of social connectedness affects trauma-induced intrusions and the neural processing of fear signals. Moreover, it is uncertain, whether loneliness plays a different role in women and men. We used a prestratification strategy and recruited n=47 (n=20 women) healthy individuals with high loneliness and n=35 controls (n=18 women). Participants were exposed to an experimental trauma and evoked intrusive thoughts in daily life were monitored for three consecutive days. Functional magnetic resonance imaging was used to assess neural habituation to fearful faces and fear learning (conditioning and extinction) prior to trauma exposure. The total number of intrusions and amygdala reactivity in neural fear processing served as the primary study outcomes. Our results revealed a significant interaction between loneliness and sex such that loneliness was associated with more intrusions in men, but not in women. A similar pattern emerged at the neural level, with both reduced amygdala habituation to repeated fearful faces and amygdala hyperreactivity during the conditioning of fear signals in lonely men, but not in women. Our findings indicate that loneliness may confer vulnerability to intrusive memories after trauma exposure in healthy men and that this phenotype relates to altered limbic processing of fear signals. Collectively, interventions targeting social connectedness may mitigate the sequelae of traumatic experiences.

neuroscience↗

bioRxiv2021

Loneliness and the social brain: how perceived social isolation impairs human interactions

Loneliness is a painful condition associated with increased risk for premature mortality. The formation of new, positive social relationships can alleviate feelings of loneliness, but requires rapid trustworthiness decisions during initial encounters and it is still unclear how loneliness hinders interpersonal trust. Here, we use a multimodal approach including behavioral, psychophysiological, hormonal, and neuroimaging measurements to probe a trust-based mechanism underlying impaired social interactions in loneliness. Pre-stratified healthy individuals with high loneliness scores (n = 42 out of a screened sample of 3678 adults) show reduced oxytocinergic and affective responsiveness to a positive conversation, report less interpersonal trust, and prefer larger social distances compared to controls (n = 40). Moreover, lonely individuals are rated as less trustworthy compared to controls and identified by the blinded confederate better than chance. During initial trust decisions, lonely individuals exhibit attenuated limbic and striatal activation and blunted functional connectivity between the anterior insula and occipitoparietal regions, which correlates with the diminished affective responsiveness to the positive social interaction. This neural response pattern is not mediated by loneliness-associated psychological symptoms. Thus, our results indicate compromised integration of trust-related information as a shared neurobiological component in loneliness, yielding a reciprocally reinforced trust bias in social dyads.

neuroscience↗