Biology subjects

Schirmer, A.

Publications and source records attributed to Schirmer, A..

3 recordsLinked to original sources

bioRxiv2024

High distinctness of circadian rhythm is related to negative emotionality and enhanced neural processing of punishment-related information in men

For years, research on the human biological clock has focused primarily on chronotype (phase of the circadian rhythm). However, a second dimension - distinctness (subjective amplitude) of the rhythm, has so far been overlooked. This study aimed to explore the intricate interplay between psychometric traits and reward-punishment processing, considering both chronotype and distinctness. Circadian rhythmicity characteristics of 37 healthy men (aged 20-30) were measured using the Morningness-Eveningness-Stability-Scale improved (MESSi) questionnaire. We also employed a battery of psychometric questionnaires and used functional magnetic resonance (fMRI) during the Monetary Incentive Delay task, which is a common method of assessing reward-punishment processing. We found a positive association between distinctness and the activity in the bilateral Superior Frontal Gyrus (SFG), Supplementary Motor Area (SMA) and Ventral Tegmental Area (VTA) during processing of punishment cues. These results are consistent with psychometric findings - a significant positive association between distinctness and sensitivity to punishment, neuroticism, behavioral inhibition system (BIS), attention deficits, and negative emotionality. As regards eveningness, we found its negative association only with sensitivity to punishment and BIS. These results highlight the crucial role of distinctness in human functioning, especially in terms of punishment processing and negative emotionality.

neuroscience↗

bioRxiv2021

Discriminative and affective touch converge: Somatosensory cortex represents A-beta input in a CT-like manner

Current theory divides the human mechanical sense into discriminative and affective systems. A discriminative system supports tactile exploration and manipulation via fast A{beta} signaling, whereas an affective system supports the pleasure of friendly interpersonal touch via slow CT signaling. To probe this system segregation, we recorded the electroencephalogram from participants being stroked and reporting stroke pleasantness. We observed a somatosensory negativity that was maximal for CT optimal as compared with sub-optimal velocities, that predicted subjective pleasantness, and showed only for stroking of hairy skin known to be CT innervated. Importantly, the latency of this negativity preceded C fiber input to the brain by several hundred milliseconds and is best explained by interactions between CT and A{beta} processes in the spinal cord. Our data challenge the divide between discriminative and affective touch implying instead that both fast A{beta} and slow CT signaling play an important role in tactile pleasure.

neuroscience↗

bioRxiv2017

Familiarity with companions aids recovery from fear inzebrafish

Interaction with social partners during or after a stressful episode aids recovery in humans and other mammals. We asked if a comparable phenomenon exists in zebrafish (Danio rerio) that live in shoals in the wild. In the first experiment, we observed that most quantifiable parameters of swimming behavior were similar when zerbafish swam alone or with companions. However, after exposure to an alarm substance (Schreckstoff), individuals recovering alone continued to display behaviors associated with fear after removal of the stimulus, while those recovering with companions did not. In the next two experiments, we examined the role of familiarity of companions. Subjects spent more time in the vicinity of familiar companions in a two-choice assay. While both familiar and unfamiliar companions reduced behavioral signs of distress, familiar companions additionally modulated cortisol and endogenous isotocin in subjects. Shortly after being united with familiar companions, isotocin spiked followed by a dampening of circulating cortisol levels. These results suggest that zebrafish experience fear attenuation in the presence of others and familiar companions are more effective at buffering the stress associated with escaping predation. Changes in behavior, circulating cortisol and isotocin levels due to social partners are reminiscent of changes due to amelioration of fear in some mammalian species in the presence of companions. The two phenomena may be related.

animal behavior and cognition↗