Biology subjects

Vallat, R.

Publications and source records attributed to Vallat, R..

3 recordsLinked to original sources

bioRxiv2021

Increase of both bottom-up and top-down attentional processes in high dream recallers

Event-related potentials (ERPs) associated with the involuntary orientation of (bottom-up) attention towards an unexpected sound are of larger amplitude in high dream recallers (HR) than in low dream recallers (LR) during passive listening, suggesting different attentional functioning. We measured bottom-up and top-down attentional performance and their cerebral correlates in 18 HR (11 women, age = 22.7 {+/-} 4.1 years, dream recall frequency = 5.3 {+/-} 1.3 days with a dream recall per week) and 19 LR (10 women, age = 22.3, DRF = 0.2 {+/-}0.2) using EEG and the Competitive Attention Task. Between-group differences were found in ERPs but not in behavior. The results confirm that HR present larger ERPs to distracting sounds than LR during active listening, suggesting enhanced bottom-up processing of irrelevant sounds. HR also presented a larger contingent negative variation during target expectancy and a larger P3b response to target sounds than LR, speaking for an enhanced recruitment of top-down attention. Enhancement of both top-down and bottom-up processes in HR leads to an apparently preserved attentional balance since similar performance were observed in the two groups. Therefore, different neurophysiological profiles can result in similar cognitive performance, with some profiles possibly costlier in term of resource/energy consumption.

neuroscience↗

bioRxiv2021

A universal, open-source, high-performance tool for automated sleep staging

The creation of a completely automated sleep-scoring system that is highly accurate, flexible, well validated, free and simple to use by anyone has yet to be accomplished. In part, this is due to the difficulty of use of existing algorithms, algorithms having been trained on too small samples, and paywall demotivation. Here we describe a novel algorithm trained and validated on +27,000 hours of polysomnographic sleep recordings across heterogeneous populations around the world. This tool offers high sleep-staging accuracy matching or exceeding human accuracy and interscorer agreement no matter the population kind. The software is easy to use, computationally low-demanding, open source, and free. Such software has the potential to facilitate broad adoption of automated sleep staging with the hope of becoming an industry standard.

bioinformatics↗

bioRxiv2021

Sleep Loss Impacts the Interconnected Brain-Body-Mood Regulation of Cardiovascular Function in Humans

Poor sleep is associated with hypertension, a major risk factor for cardiovascular disease1,2. However, the mechanism(s) through which sleep loss impacts blood pressure remain largely unknown, including the inter-related brain and peripheral body systems that regulate vascular function3. In a repeated-measures experimental study of 66 healthy adult participants, we demonstrate four core findings addressing this question. First, a night of sleep loss significantly increased blood pressure--both systolic and diastolic, yet this change in vascular tone was independent of any increase in heart rate. Second, sleep loss compromised functional brain connectivity within regions that regulate vascular tone. Third, sleep-loss related changes in brain connectivity and vascular tone were significantly inter-dependent, with changes in brain nodes explaining the shift towards hypertension. Fourth, sleep-loss related changes in mood, specifically reductions in positive and amplification in negative states, each demonstrated an interaction with the impairments in brain connectivity and blood pressure. Together, these findings support an embodied framework in which sleep loss confers increased risk of cardiovascular disease through interactions between brain homeostatic control, mood-state and blood pressure.

neuroscience↗