Vergara Pablo, Sakaguchi Masanori
International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, Tsukuba, Japan.
Front Cell Neurosci. 2020 Nov 26;14:594401. doi: 10.3389/fncel.2020.594401. eCollection 2020.
The mammalian hippocampus generates new neurons that incorporate into existing neuronal networks throughout the lifespan, which bestows a unique form of cellular plasticity to the memory system. Recently, we found that hippocampal adult-born neurons (ABNs) that were active during learning reactivate during subsequent rapid eye movement (REM) sleep and provided causal evidence that ABN activity during REM sleep is necessary for memory consolidation. Here, we describe the potential underlying mechanisms by highlighting distinct characteristics of ABNs including decoupled firing from local oscillations and ability to undergo profound synaptic remodeling in response to experience. We further discuss whether ABNs constitute the conventional definition of engram cells by focusing on their active and passive roles in the memory system. This synthesis of evidence helps advance our thinking on the unique mechanisms by which ABNs contribute to memory consolidation.
哺乳动物海马体在整个生命周期中都会产生新的神经元，这些神经元会融入现有的神经网络，赋予记忆系统一种独特的细胞可塑性形式。最近，我们发现学习过程中活跃的海马体成年新生神经元（ABNs）在随后的快速眼动（REM）睡眠期间会重新激活，并提供了因果证据，表明REM睡眠期间ABN的活动对于记忆巩固是必要的。在这里，我们通过强调ABNs的独特特征来描述潜在的机制，这些特征包括与局部振荡解耦的放电以及响应经验进行深度突触重塑的能力。我们进一步通过关注它们在记忆系统中的主动和被动作用，来讨论ABNs是否构成记忆印迹细胞的传统定义。这一证据的综合有助于推进我们对ABNs促进记忆巩固的独特机制的思考。
