Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.04.30.070466v1?rss=1 Authors: Clawson, B., Pickup, E., Ensing, A., Geneseo, L., Shaver, J., Gonzalez-Amoretti, J., Zhao, M., York, A. K., Jiang, S., Aton, S. Abstract: Learning-activated engram neurons play a critical role in memory recall. An untested hypothesis is that these same neurons play an instructive role in offline memory consolidation. Here we show that a visually-cued fear memory is consolidated during post-conditioning sleep in mice. We then use TRAP (targeted recombination in active populations) to genetically label or optogenetically manipulate primary visual cortex (V1) neurons responsive to the visual cue . Following fear conditioning, mice respond to activation of this visual engram population in a manner similar to visual presentation of fear cues. Cue-responsive neurons are selectively reactivated in V1 during post-conditioning sleep. Mimicking visual engram reactivation optogenetically leads to increased representation of the visual cue in V1. Optogenetic inhibition of the engram population during post-conditioning sleep disrupts consolidation of fear memory. We conclude that selective sleep-associated reactivation of learning-activated sensory populations serves as a necessary instructive mechanism for memory consolidation. Copy rights belong to original authors. Visit the link for more info