An optimal oscillatory phase for pattern reactivation during memory retrieval

Kerrén, C., Linde-Domingo, J., Hanslmayr, S. and Wimber, M. (2018) An optimal oscillatory phase for pattern reactivation during memory retrieval. Current Biology, 28(21), 3383-3392.e6. (doi: 10.1016/j.cub.2018.08.065) (PMID:30344116)

Abstract

Computational models and in vivo studies in rodents suggest that the hippocampal system oscillates between states that are optimal for encoding and states that are optimal for retrieval. Here, we show that in humans, neural signatures of memory reactivation are modulated by the phase of a theta oscillation. Electroencephalography (EEG) was recorded while participants were cued to recall previously learned word-object associations, and time-resolved pattern classifiers were trained to detect neural reactivation of the target objects. Classifier fidelity rhythmically fluctuated at 7 or 8 Hz and was modulated by theta phase across the entire recall period. The phase of optimal classification was shifted approximately 180° between encoding and retrieval. Inspired by animal work, we then computed “classifier-locked averages” to analyze how ongoing theta oscillations behaved around the time points at which the classifier indicated memory retrieval. We found strong theta (7 or 8 Hz) phase consistency approximately 300 ms before the time points of maximal neural memory reactivation. Our findings provide important evidence that the neural signatures of memory retrieval fluctuate and are time locked to the phase of an ongoing theta oscillation.

• Item Type: Articles
• Additional Information: his work was supported by a fellowship from Stiftelsen Olle Engkvist Byggmästare awarded to M.W., a PhD scholarship from the BBSRC Midlands Integrative Biosciences Training Partnership (MIBTP) awarded to J.L.-D. and M.W., and C.K. and a starting grant from the European Research Council awarded to M.W. (ERC-2016-STG-715714).
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Hanslmayr, Professor Simon and Wimber, Professor Maria

Creator Roles

Hanslmayr, S.: Methodology, Writing – review and editing

• Authors: Kerrén, C., Linde-Domingo, J., Hanslmayr, S., and Wimber, M.
• College/School: College of Medical Veterinary and Life Sciences > School of Psychology & Neuroscience
• Journal Name: Current Biology
• Publisher: Elsevier (Cell Press)
• ISSN: 0960-9822
• ISSN (Online): 1879-0445
• Published Online: 18 October 2018
• Copyright Holders: Copyright © 2018 Elsevier Ltd.
• First Published: First published in Current Biology 28(21): 3383-3392.e6
• Publisher Policy: Reproduced in accordance with the publisher copyright policy