Center for Neural Science, New York University, 4 Washington Place, New York, NY 10003, USA.
Center for Neural Science, New York University, 4 Washington Place, New York, NY 10003, USA.
Cell Rep. 2022 Nov 15;41(7):111643. doi: 10.1016/j.celrep.2022.111643.
Episodic memories formed in early childhood rapidly decay, but their latent traces remain stored long term. These memories require the dorsal hippocampus (dHPC) and seem to undergo a developmental critical period. It remains to be determined whether the maturation of parvalbumin interneurons (PVIs), a major mechanism of critical periods, contributes to memory development. Here, we show that episodic infantile learning significantly increases the levels of parvalbumin in the dHPC 48 h after training. Chemogenetic inhibition of PVIs before learning indicated that these neurons are required for infantile memory formation. A bilateral dHPC injection of the γ-aminobutyric acid type A receptor agonist diazepam after training elicited long-term memory expression in infant rats, although direct PVI chemogenetic activation had no effect. Finally, PVI activity was required for brain-derived neurotrophic factor (BDNF)-dependent maturation of memory competence, i.e., adult-like long-term memory expression. Thus, dHPC PVIs are critical for the formation of infantile memories and for memory development.
儿童早期形成的情景记忆迅速衰退，但它们的潜在痕迹会长期储存。这些记忆需要背侧海马体（dHPC），并且似乎经历了一个发育关键期。目前还不确定关键期的主要机制之一——小白蛋白中间神经元（PVIs）的成熟是否有助于记忆的发展。在这里，我们发现情景性婴儿学习在训练后 48 小时显著增加了 dHPC 中的小白蛋白水平。学习前对 PVIs 的化学遗传抑制表明，这些神经元是婴儿记忆形成所必需的。训练后，双侧 dHPC 注射γ-氨基丁酸 A 型受体激动剂地西泮可诱发幼鼠的长期记忆表达，尽管直接对 PVIs 进行化学遗传激活没有效果。最后，PVIs 的活动对于脑源性神经营养因子（BDNF）依赖性记忆能力的成熟是必需的，即成年样的长期记忆表达。因此，dHPC 的 PVIs 对于婴儿记忆的形成和记忆的发展至关重要。
