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Updated: Nov 5, 2025
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Quantifying Infra-slow Dynamics of Spectral Power and Heart Rate in Sleeping Mice
Published on: August 2, 2017
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Coupling between slow waves and sharp-wave ripples engages distributed neural activity during sleep in humans
Ivan Skelin1,2, Haoxin Zhang3,4, Jie Zheng4
1Department of Neurology, University of California, Irvine, CA 92603; iskelin@uci.edu linjj@hs.uci.edu.
Summary
During sleep, synchronized brain activity, including sharp-wave ripples (SWRs) and slow-wave activity (SWA), helps consolidate memories. This study reveals how hippocampal SWRs coordinate with cortical SWA to engage brain networks for memory formation.
Area of Science:
- Neuroscience
- Sleep Science
- Cognitive Neuroscience
Background:
- Memory consolidation during sleep relies on synchronized neuronal activity.
- The precise mechanisms linking hippocampal sharp-wave ripples (SWRs) with subcortical/cortical activity remain unclear.
Purpose of the Study:
- To investigate the role of hippocampal SWRs in coordinating distributed neuronal ensembles during sleep.
- To examine how SWRs interact with slow-wave activity (SWA) and sleep spindles (SP) to modulate brain activity and functional connectivity.
Main Methods:
- Intracranial electrophysiological recordings from human hippocampus, amygdala, temporal, and frontal cortices.
- Analysis of high-frequency activity (HFA) modulation during SWRs.
- Assessment of coupling between SWRs, SWA, and SP, and their prediction of functional connectivity.
Main Results:
- Hippocampal SWRs significantly modulate high-frequency activity (HFA) across widespread brain regions.
- Peri-SWR HFA modulation is linked to the coupling of SWRs with local SWA or SP.
- Cortical SWA phase and SWR amplitude predict functional connectivity between frontal and temporal cortices.
Conclusions:
- Hippocampal SWRs synchronize distributed neuronal populations through interactions with cortical SWA and SP.
- This synchronization mechanism transiently engages neural networks essential for hippocampal-dependent memory consolidation during sleep.
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