# Decreased sleep is linked longitudinally and directionally to alterations in the brain’s intrinsic functional architecture

## TL;DR

This study shows that less sleep causes changes in brain connectivity in adolescents over time.

## Contribution

The study provides causal evidence that reduced sleep leads to brain connectivity changes during adolescence.

## Key findings

- Reduced sleep is linked to a consistent brain connectivity pattern in adolescents.
- Sleep deprivation increases this connectivity pattern in adults.
- Changes in sleep cause characteristic brain connectivity changes during adolescence.

## Abstract

Previous cross-sectional studies demonstrated that reduced sleep is associated with widespread changes in the brain’s intrinsic functional architecture. The present study extends this work by clarifying links between sleep and the developing brain during adolescence both longitudinally (across two years) and directionally (does reduced sleep cause connectivity changes or are connectivity changes the cause of reduced sleep?). Our novel approach combines the Adolescent Brain Cognitive Development (ABCD) Study, a longitudinal observational study of 11,878 youth, and a second sample of 76 adult participants scanned after a typical night of sleep and after a sleep deprivation causal manipulation. First, in the ABCD dataset, we identified a robust and generalizable neurosignature of reduced sleep. Second, in an independent sample of ABCD participants, we demonstrate that greater reductions in sleep duration across two years are significantly related to greater expression of this neurosignature. Third, in the sleep deprivation dataset, we show that expression of the ABCD reduced sleep neurosignature is significantly increased within individuals following sleep deprivation, and that neurosignatures of reduced sleep from the two samples exhibit significant spatial correspondence. These results clarify links between sleep and the developing brain and provide novel evidence that changes in sleep produce characteristic brain functional connectivity changes across adolescence.