Sleep inconsistency between weekends and weekdays is associated with changes in brain function during task and rest

Area of Science:

• Neuroscience
• Sleep Science
• Cognitive Psychology

Background:

• Sleep deprivation and circadian rhythm disruptions negatively impact cognitive functions.
• Limited research exists on the effects of sleep inconsistency on behavior and brain function.

Purpose of the Study:

• To investigate the correlation between weekend-weekday sleep duration and timing inconsistencies and changes in behavior and brain function.
• To examine brain activity during a visual attention task and at rest using fMRI.

Main Methods:

• Actigraphy data collected over one week to calculate weekend-weekday sleep duration and midpoint differences.
• 3 Tesla fMRI scans to measure brain activity during a visual attention task and resting-state conditions in 56 healthy adults.

Main Results:

• Weekend-weekday sleep duration and timing inconsistencies were uncorrelated and had distinct effects.
• Longer weekend sleep duration correlated with improved attentional performance and enhanced default mode network (DMN) deactivation and connectivity.
• Later weekend sleep timing correlated with worse performance, reduced occipital activation, and decreased resting-state functional connectivity (RSFC) within the DMN.

Conclusions:

• Consistent sleep timing is crucial for optimal brain function, particularly for the DMN.
• Weekend 'catch-up' sleep, specifically longer sleep duration, demonstrates benefits for cognitive performance and brain function in healthy adults.