Biology subjects

Watford, L.

Publications and source records attributed to Watford, L..

3 recordsLinked to original sources

bioRxiv2026

Vagally Mediated Heart Rate Variability During REM Sleep is Associated with Retention of Fear Extinction in Generalized Anxiety Disorder

Fear extinction processes are central to the pathology and treatment of anxiety disorders. Emerging evidence implicates rapid eye movement (REM) sleep in the consolidation of extinction memory. Separately, converging theory and empirical work suggest that vagally mediated heart rate variability (VmHRV) serves as a peripheral index of cortico-subcortical regulatory capacity relevant to extinction circuitry. On this basis, we tested the hypothesis that VmHRV during REM sleep would be associated with the retention of extinction memory in individuals with generalized anxiety disorder (GAD). Participants underwent a validated two-day fear conditioning and extinction paradigm. Subjective extinction retention (sERI) was quantified during a recall test 24 hours after learning and ambulatory polysomnography was recorded on the intervening night. As hypothesized, higher REM VmHRV was significantly associated with better extinction retention. This association remained robust after controlling psychotropic medication use and REM density. In contrast, VmHRV during SWS or wakefulness, as well as other REM sleep measures, were not associated with extinction retention. These findings identify REM VmHRV as a significant predictor of extinction memory retention in GAD, extending prior findings in trauma-exposed individuals. We propose that reduced vagal tone indexes compromised prefrontal inhibitory control over amygdala and noradrenergic circuits, thereby impairing REM sleep-dependent consolidation. These results position VmHRV during REM sleep as a potential transdiagnostic biomarker of extinction memory processing and suggest that interventions enhancing vagal tone could improve treatment outcomes in anxiety disorders.

neuroscience↗

bioRxiv2024

Poor Self-Reported Sleep is Associated with Prolonged White Matter T2 Relaxation in Psychotic Disorders

BackgroundSchizophrenia (SZ) and bipolar disorder (BD) are characterized by white matter (WM) abnormalities, however, their relationship with illness presentation is not clear. Sleep disturbances are common in both disorders, and recent evidence suggests that sleep plays a critical role in WM physiology. Therefore, it is plausible that sleep disturbances are associated with impaired WM integrity in these disorders. To test this hypothesis, we examined the association of self-reported sleep disturbances with WM transverse (T2) relaxation times in patients with SZ spectrum disorders and BD with psychotic features. Methods28 patients with psychosis (17 BD-I, with psychotic features and 11 SZ spectrum disorders) were included. Metabolite and water T2 relaxation times were measured in the anterior corona radiata at 4T. Sleep was evaluated using the Pittsburgh Sleep Quality Index. ResultsPSQI total score showed a moderate to strong positive correlation with water T2 (r = 0.64, p<0.001). Linear regressions showed that this association was specific to sleep disturbance but was not a byproduct of exacerbation in depressive, manic, or psychotic symptoms. In our exploratory analysis, sleep disturbance was correlated with free water percentage, suggesting that increased extracellular water may be a mechanism underlying the association of disturbed sleep and prolonged water T2 relaxation. ConclusionOur results highlight the connection between poor sleep and WM abnormalities in psychotic disorders. Future research using objective sleep measures and neuroimaging techniques suitable to probe free water is needed to further our insight into this relationship.

neuroscience↗

bioRxiv2023

REM Sleep Measures and REM Vagal Activity Predict Extinction Recall in Trauma-Exposed Individuals

Accumulating evidence suggests that rapid eye movement sleep (REM) supports the consolidation of extinction memory. REM is disrupted in PTSD, and REM abnormalities after traumatic events increase the risk of developing PTSD. Therefore, it was hypothesized that abnormal REM in trauma-exposed individuals may pave the way for PTSD by interfering with the processing of extinction memory. In addition, PTSD patients display reduced vagal activity. Vagal activity contributes to the strengthening of memories, including fear extinction memory, and recent studies show that the role of vagus in memory processing extends to memory consolidation during sleep. Therefore, it is plausible that reduced vagal activity during sleep in trauma-exposed individuals may be an additional mechanism that impairs extinction memory consolidation. However, to date, the contribution of sleep vagal activity to the consolidation of extinction memory or any emotional memory has not been investigated. To test these hypotheses, we examined the association of extinction memory with REM characteristics and REM vagal activity (indexed as heart rate variability) in a large sample of trauma-exposed individuals (n=113). Consistent with our hypotheses, REM disruption was associated with poorer physiological and explicit extinction memory. Furthermore, higher vagal activity during REM was associated with better explicit extinction memory, and physiological extinction memory in males. These findings support the notion that abnormal REM may contribute to PTSD by impairing the consolidation of extinction memory and indicate the potential utility of interventions that target REM sleep characteristics and REM vagal activity in fear-related disorders.

neuroscience↗