Biology subjects

Wilhelm-Groch, I.

Publications and source records attributed to Wilhelm-Groch, I..

4 recordsLinked to original sources

bioRxiv2025

Sleep to remember, sleep to protect: increased sleep spindle and theta activity predict fewer intrusive memories after analogue trauma

Recent evidence shows a strong correlative link between sleep disturbances and intrusive memories after traumatic events, presumably due to insufficient (nocturnal) memory integration. However, the underlying mechanisms of this link and the role of specific neural activities during sleep are poorly understood so far. Here, we investigated how the intra-individual affective response to an experimental trauma predicts changes in oscillatory activity during subsequent sleep and how these changes predict the processing of the experimental trauma. In a randomized within-subject comparison, twenty-two female, healthy participants (23.14 {+/-} 2.46 years) watched a well-validated film clip including "traumatic" contents and a neutral film clip before bedtime on two separate nights. Heart rate was recorded during the film clips and nocturnal brain activity was recorded using 64-channel high-density EEG during subsequent nights. Intrusive memories were assessed via a seven-days diary and negative affect was assessed using laboratory trauma film reminders one week after the trauma film. An increased intra-individual heart rate during the trauma film predicted higher intra-individual sleep spindle amplitude the following night. Increased theta activity (4.25 - 8 Hz) during rapid eye movement (REM) sleep after the trauma film predicted fewer trauma film related intrusive memories and negative affect. Likewise, an increase in sleep spindles after the trauma film predicted fewer trauma film related intrusive memories. Our findings suggest that an experience-dependent up-regulation of these nocturnal oscillatory activity patterns, which are known to be involved in adaptive memory consolidation processes, serves as a protective factor against trauma-related intrusive memory development. Particularly, increased theta activity during REM sleep and sleep spindle activity seem to be of importance here.

neuroscience↗

bioRxiv2025

Reactivating a relaxation exercise during sleep to influence cortical hyperarousal in people with frequent nightmares - a randomized crossover trial

Study ObjectivesHigh-frequency EEG activity during sleep (cortical hyperarousal), is a transdiagnostic feature across psychiatric disorders, including nightmare disorder. It is discussed as a target of intervention; however, specific treatment options are yet unavailable. We tested whether exposure to relaxation-associated odor cues during sleep would reduce cortical hyperarousal, i.e. beta (16.25 - 31 Hz), gamma (31.25 - 45 Hz), spindle activity and nightmare occurrence in participants with frequent nightmares. MethodsTwenty-five (21 female, mean age (SD) = 24.94(5.01)) participants, recruited from undergraduate students at University of Luebeck, with [≥]1 nightmare / week received a deep breathing relaxation intervention for one week coupled with an odor. On two subsequent nights in the sleep laboratory, the associated odor (A), or control odor (B) were presented in randomized order in a crossover design with randomization at baseline; participants were blinded to intervention. ResultsN = 11 participants were allocated to AB and n = 14 to BA sequence. Exposure to relaxation-associated odor cues during sleep did not affect beta or gamma activity while spindle count and density were significantly reduced. Reduction in spindle count during reactivation nights correlated with reduced subjective wake-after-sleep-onset. There was no additional impact on nightmare symptoms. There were no adverse events or side effects. ConclusionsThe reactivation of relaxation-associated states with odor cues during sleep may be associated with changes in spectral activity, specifically spindle activity. Future studies should implement multiple nights of reactivation and include different patient groups with cortical hyperarousal to test the transdiagnostic potential of this new intervention.

neuroscience↗

bioRxiv2024

Time-of-day related fluctuations of self-belief formation

Time of day influences a variety of human cognitive processes, including attention, executive functions and memory formation, as well as affective experiences and mood. However, circadian modulations of self-related learning and belief formation, which are highly affected by emotional states, remain poorly understood. Here, we present results from exploratory post-hoc analyses on data aggregated from five studies assessing the formation of self-related ability beliefs. A total of N=242 healthy participants completed a validated learning task at different times of the day, during which they continuously received feedback on their performance. Computational modeling was applied to quantify participants learning behavior during the task. Results suggest an association between time-of-day and self-belief formation, showing that participants who were tested in the evening (7:00-9:59 p.m.) updated their self-beliefs more strongly in response to the received feedback compared to those tested in the afternoon (1:00-3:59 p.m.). Evidence from additional models indicated that these differences were driven by non-linear, rhythmic changes in self-belief formation across different times of the day. Future studies should systematically examine within-subject fluctuations in self-belief formation across the day and address the influence of individual factors such as chronotype, age, mood and sleep quality. Understanding circadian modulations of self-related belief formation could contribute to optimized interventions for conditions characterized by maladaptive self-beliefs, such as depression, as well as in academic contexts.

neuroscience↗

bioRxiv2024

Neurocomputational Mechanisms Underlying Maladaptive Self-Belief Formation in Depression

Maladaptive self-beliefs are a core symptom of major depressive disorder. These beliefs are perpetuated by a negatively biased integration of self-related feedback. Understanding the neurocomputational mechanisms of biased belief updating may help to counteract maladaptive beliefs and the maintenance of depression. The present study uses a belief-updating task and functional neuroimaging to examine the neurocomputational mechanisms associated with self-related feedback processing in individuals with major depression and matched healthy controls. We hypothesized that increased symptom burden in depression is associated with negatively biased self-belief updating and altered neural tracking of social feedback. Our findings show that depression is related to reduced incorporation of unexpected positive feedback, with higher symptom burden alongside heightened insula reactivity to unexpected negative feedback. The interplay of increased neural responsiveness to negative feedback and the reduced learning from positive feedback provide new insights into cognitive distortions in depression and may explain the persistence of maladaptive self-beliefs and, thus, the maintenance of depression.

neuroscience↗