Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, USA.
Universidad Ana G. Mendez, Recinto de Gurabo, Gurabo, Puerto Rico.
Nat Commun. 2021 Feb 22;12(1):1200. doi: 10.1038/s41467-021-21471-2.
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.
学习激活的记忆神经元在记忆回忆中起着关键作用。一个未经检验的假设是，这些相同的神经元在离线记忆巩固中起着指导作用。在这里，我们表明，在小鼠的后条件睡眠期间，视觉提示的恐惧记忆得到巩固。然后，我们使用 TRAP（靶向在活跃群体中的重组）来遗传标记或光遗传学操纵对视觉提示有反应的主要视觉皮层（V1）神经元。在恐惧条件作用后，小鼠对该视觉记忆痕迹群体的激活的反应类似于恐惧提示的视觉呈现。在条件后睡眠期间，在 V1 中选择性地重新激活线索反应神经元。光遗传学上模拟视觉记忆痕迹的再激活会导致 V1 中视觉提示的表示增加。在条件后睡眠期间，光遗传学抑制记忆痕迹群体会破坏恐惧记忆的巩固。我们的结论是，学习激活的感觉群体的选择性睡眠相关再激活是记忆巩固的必要指导机制。
