Flexibility of brain regions during working memory curtails cognitive consequences to lack of sleep

TL;DR

This study demonstrates that brain regions increase their flexibility during working memory tasks after poor sleep, enabling performance to remain stable despite sleep deprivation, highlighting neural resilience and adaptability.

Contribution

It introduces a dynamic network approach to show how brain flexibility compensates for sleep loss without affecting task performance.

Findings

Brain region flexibility increases after low sleep episodes.

Performance remains stable despite sleep deprivation.

Neural networks adapt through resource recruitment and expansion.

Abstract

Previous research has shown a clear relationship between sleep and memory, examining the impact of sleep deprivation on key cognitive processes over very short durations or in special populations. Here, we show, in a longitudinal 16 week study, that naturalistic, unfettered sleep modulations in healthy adults have significant impacts on the brain. Using a dynamic networks approach combined with hierarchical statistical modelling, we show that the flexibility of particular brain regions that span a large network including regions in occipital, temporal, and frontal cortex increased when participants performed a working memory task following low sleep episodes. Critically, performance itself did not change as a function of sleep, implying adaptability in brain networks to compensate for having a poor night's sleep by recruiting the necessary resources to complete the task. We further explore whether this compensatory effect is driven by a (i) increase in the recruitment of network resources over time and/or (ii) an expansion of the network itself. Our results add to the literature linking sleep and memory, provide an analytical framework in which to investigate compensatory modulations in the brain, and highlight the brain's resilience to day-to-day fluctuations of external pressures to performance.