Neuron
Volume 107, Issue 3, 5 August 2020, Pages 552-565.e10
Journal home page for Neuron

Article
Sparse Activity of Hippocampal Adult-Born Neurons during REM Sleep Is Necessary for Memory Consolidation

https://doi.org/10.1016/j.neuron.2020.05.008Get rights and content
Under an Elsevier user license
open archive

Highlights

  • Adult-born neuron (ABN) activity during sleep can be seen using Ca2+ imaging

  • ABNs active after learning reactivate in subsequent rapid eye movement (REM) sleep

  • Optogenetic manipulation of ABN activity in REM sleep impairs memory consolidation

  • This effect may be mediated by ABN synaptic plasticity

Summary

The occurrence of dreaming during rapid eye movement (REM) sleep prompts interest in the role of REM sleep in hippocampal-dependent episodic memory. Within the mammalian hippocampus, the dentate gyrus (DG) has the unique characteristic of exhibiting neurogenesis persisting into adulthood. Despite their small numbers and sparse activity, adult-born neurons (ABNs) in the DG play critical roles in memory; however, their memory function during sleep is unknown. Here, we investigate whether young ABN activity contributes to memory consolidation during sleep using Ca2+ imaging in freely moving mice. We found that contextual fear learning recruits a population of young ABNs that are reactivated during subsequent REM sleep against a backdrop of overall reduced ABN activity. Optogenetic silencing of this sparse ABN activity during REM sleep alters the structural remodeling of spines on ABN dendrites and impairs memory consolidation. These findings provide a causal link between ABN activity during REM sleep and memory consolidation.

Keywords

adult neurogenesis
memory consolidation
REM sleep
miniaturized microscope
optogenetics
calcium imaging

Cited by (0)

12

These authors contributed equally

13

Lead Contact