Reconfigurations in brain networks upon awakening from slow wave sleep: Interventions and implications in neural communication

Abstract

Sleep inertia is the brief period of impaired alertness and performance experienced immediately after waking. Little is known about the neural mechanisms underlying this phenomenon. A better understanding of the neural processes during sleep inertia may offer insight into the awakening process. We observed brain activity every 15 minutes for 1 hour following abrupt awakening from slow wave sleep during the biological night. Using 32-channel electroencephalography, a network science approach, and a within-subject design, we evaluated power, clustering coefficient, and path length across frequency bands under both a control and a polychromatic short-wavelength-enriched light intervention condition. We found that under control conditions, the awakening brain is typified by an immediate reduction in global theta, alpha, and beta power. Simultaneously, we observed a decrease in the clustering coefficient and an increase in path length within the delta band. Exposure to light immediately after awakening ameliorated changes in clustering. Our results suggest that long-range network communication within the brain is crucial to the awakening process and that the brain may prioritize these long-range connections during this transitional state. Our study highlights a novel neurophysiological signature of the awakening brain and provides a potential mechanism by which light improves performance after waking.

The Effect of Sleep Deprivation on Brain Fingerprint Stability: A Magnetoencephalography Validation Study

“…The high amplitude of the signals in this frequency band is often associated with deep sleep [41], but numerous studies report that this band also plays a role in the wakeful state, such as in the case of neocortical background activity, memory consolidations, and plasticity modulations [42,43]. Activity in the delta band has also been found to be altered due to sleep inertia effects [44,45] that may also last hours [46]. This may explain why we found such instability in the delta band, even though specific study designs are needed to fully confirm this statement.…”