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Electrophysiological signatures underlying variability in human memory consolidation

Psychology

Electrophysiological signatures underlying variability in human memory consolidation

W. Duan, Z. Xu, et al.

Targeted memory reactivation during human NREM sleep selectively enhanced object–location memories by eliciting two discrete reactivation sweeps: an initial phase of strengthened hippocampal–cortical communication with hippocampal ripples and cortical high‑frequency activity, followed by reduced coupling but increased cortical spindle activity supporting long‑term storage. Research conducted by Wei Duan, Zhansheng Xu, Dong Chen, Jing Wang, Jiali Liu, Zheng Tan, Xue Xiao, Pengcheng Lv, Mengyang Wang, Ken A. Paller, Nikolai Axmacher, and Liang Wang.... show more
Abstract
We experience countless pieces of new information each day, but remembering them later depends on firmly instilling memory storage in the brain. Numerous studies have implicated non-rapid eye movement (NREM) sleep in consolidating memories via interactions between hippocampus and cortex. However, the temporal dynamics of this hippocampal-cortical communication and the concomitant neural oscillations during memory reactivations remains unclear. To address this issue, the present study used the procedure of targeted memory reactivation (TMR) following learning of object-location associations to selectively reactivate memories during human NREM sleep. Cortical pattern reactivation and hippocampal-cortical coupling were measured with intracranial EEG recordings in patients with epilepsy. We found that TMR produced variable amounts of memory enhancement across a set of object-location associations. Successful TMR increased hippocampal ripples and cortical spindles, apparent during two discrete sweeps of reactivation. The first reactivation sweep was accompanied by increased hippocampal-cortical communication and hippocampal ripple events coupled to local cortical activity (cortical ripples and high-frequency broadband activity). In contrast, hippocampal-cortical coupling decreased during the second sweep, while increased cortical spindle activity indicated continued cortical processing to achieve long-term storage. Taken together, our findings show how dynamic patterns of item-level reactivation and hippocampal-cortical communication support memory enhancement during NREM sleep.
Publisher
Nature Communications
Published On
Mar 12, 2025
Authors
Wei Duan, Zhansheng Xu, Dong Chen, Jing Wang, Jiali Liu, Zheng Tan, Xue Xiao, Pengcheng Lv, Mengyang Wang, Ken A. Paller, Nikolai Axmacher, Liang Wang
Tags
targeted memory reactivation
NREM sleep
hippocampal ripples
cortical spindles
hippocampal-cortical coupling
intracranial EEG
memory consolidation
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