Item-specific neural representations during human sleep support long-term memory

by Jing Liu, Tao Xia, Danni Chen, Ziqing Yao, Minrui Zhu, James W. Antony, Tatia M. C. Lee, Xiaoqing Hu Understanding how individual memories are reactivated during sleep is essential in theorizing memory consolidation. Here, we employed the targeted memory reactivation (TMR) paradigm to unobtrusively replaying auditory memory cues during human participants ’ slow-wave sleep (SWS). Using representational similarity analysis (RSA) on cue-elicited electroencephalogram (EEG), we found temporally segregated and functionally distinct item-specific neural representations: the early post-cue EEG activity (within 0 to 2,000 ms) contained comparable item-spec ific representations for memory cues and control cues, signifying effective processing of auditory cues. Critically, the later EEG activity (2,500 to 2,960 ms) showed greater item-specific representations for post-sleep remembered items than for forgotten and control cues, indicating memory reproces sing. Moreover, these later item-specific neural representations were supported by concurrently increased spindles, particularly for items that had not been tested prior to sleep. These findings elucidated how external memory cues triggered item-specific neural representations during SWS and how suc h representations were linked to successful long-term memory. These results will benefit future research aiming to perturb specific memory episodes during sleep.
Source: PLoS Biology: Archived Table of Contents - Category: Biology Authors: Source Type: research