Neuron
Volume 75, Issue 4, 23 August 2012, Pages 700-713
Journal home page for Neuron

Article
Transient Slow Gamma Synchrony Underlies Hippocampal Memory Replay

https://doi.org/10.1016/j.neuron.2012.06.014Get rights and content
Under an Elsevier user license
open archive

Summary

The replay of previously stored memories during hippocampal sharp wave ripples (SWRs) is thought to support both memory retrieval and consolidation in distributed hippocampal-neocortical circuits. Replay events consist of precisely timed sequences of spikes from CA3 and CA1 neurons that are coordinated both within and across hemispheres. The mechanism of this coordination is not understood. Here, we show that during SWRs in both awake and quiescent states there are transient increases in slow gamma (20-50 Hz) power and synchrony across dorsal CA3 and CA1 networks of both hemispheres. These gamma oscillations entrain CA3 and CA1 spiking. Moreover, during awake SWRs, higher levels of slow gamma synchrony are predictive of higher quality replay of past experiences. Our results indicate that CA3-CA1 gamma synchronization is a central component of awake memory replay and suggest that transient gamma synchronization serves as a clocking mechanism to enable coordinated memory reactivation across the hippocampal network.

Highlights

► Gamma oscillations transiently increase during hippocampal sharp wave ripples ► Gamma is synchronous across CA3 and CA1 of both hemispheres ► CA3 and CA1 neurons are entrained by gamma during sharp wave ripples ► Gamma synchrony is predictive of high quality memory replay

Cited by (0)

2

Present address: CNC Program, Stanford University, Stanford, CA 94305, USA

3

Present address: Howard Hughes Medical Institute, Janelia Farm Research Campus, Ashburn, VA 20147, USA