Journal Article

Memory-enhancing properties of sleep depend on the oscillatory amplitude of norepinephrine

Dall, Camilla, Ding, Fengfei, Andersen, Mie, Feng, Jiesi, Li, Yulong, Sigurdsson, Björn, Hirase, Hajime, Hauglund, Natalie, Weikop, Pia, Nedergaard, Maiken, Kjaerby, Celia, Untiet, Verena

2022

Overview

Sleep has a complex micro-architecture, encompassing micro-arousals, sleep spindles and transitions between sleep stages. Fragmented sleep impairs memory consolidation, whereas spindle-rich and delta-rich non-rapid eye movement (NREM) sleep and rapid eye movement (REM) sleep promote it. However, the relationship between micro-arousals and memory-promoting aspects of sleep remains unclear. In this study, we used fiber photometry in mice to examine how release of the arousal mediator norepinephrine (NE) shapes sleep micro-architecture. Here we show that micro-arousals are generated in a periodic pattern during NREM sleep, riding on the peak of locus-coeruleus-generated infraslow oscillations of extracellular NE, whereas descending phases of NE oscillations drive spindles. The amplitude of NE oscillations is crucial for shaping sleep micro-architecture related to memory performance: prolonged descent of NE promotes spindle-enriched intermediate state and REM sleep but also associates with awakenings, whereas shorter NE descents uphold NREM sleep and micro-arousals. Thus, the NE oscillatory amplitude may be a target for improving sleep in sleep disorders.Kjaerby and Andersen et al. show that norepinephrine (NE) plays profound roles in shaping sleep micro-architecture. NE slowly oscillates during sleep, with NE oscillatory amplitude being a major determinant of spindle-dependent memory consolidation and awakenings.

• Publisher: Nature Publishing Group
• Subject: Activity patterns / Amplitudes / Arousal / Catecholamines / Cognitive ability / Computer architecture / Consolidation / Eye movements / Norepinephrine / NREM sleep / Oscillations / Photometry / REM sleep / Sleep / Sleep disorders