Biology subjects

Brager, A. J.

Publications and source records attributed to Brager, A. J..

2 recordsLinked to original sources

bioRxiv2025

Impact of > 24 h sustained wakefulness and subsequent recovery sleep on time-dependent changes in microRNA factors of individuals with post-acute phase mild traumatic brain injury

IntroductionThe purpose of the present study was to determine whether mild traumatic brain injury (mTBI+) results in latent changes in microRNA expression profiles across an episode of total sleep deprivation (TSD). MethodsSeven previously concussed (mTBI+) adults (24.5 {+/-} 5.3 y.o.) and 6 non-concussed control adults (mTBI-; 24.8 {+/-} 1.6 y.o.) underwent 24 h TSD (T2) preceded by 8 h baseline sleep (T1; BSL) and followed by 8 h recovery (T3; REC) sleep. Salivary microRNA expression was assessed across the entire study. ResultsSubjects (mTBI+ and mTBI-) had differential expression of salivary microRNA targets across TSD. mTBI+ subjects had greater change to microRNA expression profiles compared to mTBI- subjects between T1 and T3. DiscussionAlthough there is some evidence that TSD may unmask latent changes in gene expression in mTBI+ subjects, a definitive conclusion was precluded by differences in baseline sleep in mTBI+ (vs. mTBI-) subjects measured through polysomnography (not shown). However, this study is unique in that the mTBI+ subjects were exposed to a sleep deprivation challenge very shortly after medical clearance from mTBI demonstrating lingering neurobiological impacts of mTBI.

neuroscience↗

bioRxiv2022

Non-rapid eye movement sleep determines resilience to social stress

Resilience, the ability to overcome stressful conditions, is found in most mammals and varies significantly among individuals. A lack of resilience can lead to the development of neuropsychiatric and sleep disorders, often within the same individual. Despite extensive research into the brain mechanisms causing maladaptive behavioral-responses to stress, it is not clear why some individuals exhibit resilience. To examine if sleep has a determinative role in maladaptive behavioral-response to social stress, we investigated individual variations in resilience using a social-defeat model for male mice. Our results reveal a direct, causal relationship between sleep amount and resilience--demonstrating that sleep increases after social-defeat stress only occur in resilient mice. Further, we found that within the prefrontal cortex, a regulator of maladaptive responses to stress, pre-existing differences in sleep regulation predict resilience. Overall, these results demonstrate that increased NREM sleep, mediated cortically, is an active response to social-defeat stress that is both necessary and sufficient for promoting resilience. They also show that differences in resilience are strongly correlated with inter-individual variability in sleep regulation.

neuroscience↗