Ramsaran Adam I, Ventura Silvia, Gallucci Julia, De Snoo Mitchell L, Josselyn Sheena A, Frankland Paul W
Neurosciences & Mental Health Program, The Hospital for Sick Children, Toronto, Ontario, Canada.
Department of Psychology, University of Toronto, Toronto, Ontario, Canada.
bioRxiv. 2024 Nov 7:2024.11.06.622296. doi: 10.1101/2024.11.06.622296.
Episodic-like memory is a later-developing cognitive function supported by the hippocampus. In mice, the formation of extracellular perineuronal nets in subfield CA1 of the dorsal hippocampus controls the emergence of episodic-like memory during the fourth postnatal week (Ramsaran et al., 2023). Whether the timing of episodic-like memory onset is hard-wired, or flexibly set by early-life experiences during a critical or sensitive period for hippocampal maturation, is unknown. Here, we show that the trajectories for episodic-like memory development vary for mice given different sets of experiences spanning the second and third postnatal weeks. Specifically, episodic-like memory precision developed later in mice that experienced early-life adversity, while it developed earlier in mice that experienced early-life enrichment. Moreover, we demonstrate that early-life experiences set the timing of episodic-like memory development by modulating the pace of perineuronal net formation in dorsal CA1. These results indicate that the hippocampus undergoes a sensitive period during which early-life experiences determine the timing for episodic-like memory development.
情景样记忆是一种由海马体支持的后期发展的认知功能。在小鼠中，出生后第四周，背侧海马体CA1亚区细胞外周神经周网的形成控制着情景样记忆的出现（拉姆萨兰等人，2023年）。情景样记忆开始的时间是预先设定的，还是在海马体成熟的关键或敏感时期由早期生活经历灵活设定的，目前尚不清楚。在这里，我们表明，对于在出生后第二周和第三周经历不同经历的小鼠，情景样记忆发展的轨迹有所不同。具体而言，情景样记忆的精确性在经历早期生活逆境的小鼠中发展较晚，而在经历早期生活丰富化的小鼠中发展较早。此外，我们证明，早期生活经历通过调节背侧CA1区神经周网形成的速度来设定情景样记忆发展的时间。这些结果表明，海马体经历了一个敏感期，在此期间，早期生活经历决定了情景样记忆发展的时间。
