牛津大学David Dupret和Stephen B. McHugh共同合作近期取得重要工作进展。他们研究发现成人出生的齿状颗粒细胞促进了海马群体的稀疏性。这一研究成果2022年10月10日在线发表于《自然—神经科学》杂志上。

研究人员发现，在新刺激的记忆处理过程中，abDGCs促进稀疏性海马细胞群体突增。通过结合对行为小鼠的三重（DG-CA3-CA1）集合记录和光遗传干预，研究人员表明abDGCs构成了一个高放电率的神经元子集，对新奇事物的活动反应增强，并受到西塔（theta）振荡的强烈调节。在出生后4-7周内选择性地激活abDGCs会增加海马群体模式的稀疏性，而抑制abDGCs则会减少这种稀疏性，增加主细胞的放电率，并在不影响单神经元空间表征的情况下，降低网络放电结构的维度，从而损害新的物体识别。研究人员提出，成年出生的颗粒细胞暂时支持稀疏的海马群体活动结构，以实现与有效记忆信息处理相关的高维反应。

据了解，齿状回（DG）控制着新皮层的信息流向海马。有趣的是，DG在整个生命周期中也产生成体的齿状颗粒细胞（abDGCs），但它们对下游放电动力学的贡献尚不清楚。

附：英文原文

Title: Adult-born dentate granule cells promote hippocampal population sparsity

Author: McHugh, Stephen B., Lopes-dos-Santos, Vtor, Gava, Giuseppe P., Hartwich, Katja, Tam, Shu K. E., Bannerman, David M., Dupret, David

Issue&Volume: 2022-10-10

Abstract: The dentate gyrus (DG) gates neocortical information flow to the hippocampus. Intriguingly, the DG also produces adult-born dentate granule cells (abDGCs) throughout the lifespan, but their contribution to downstream firing dynamics remains unclear. Here, we show that abDGCs promote sparser hippocampal population spiking during mnemonic processing of novel stimuli. By combining triple-(DG-CA3-CA1) ensemble recordings and optogenetic interventions in behaving mice, we show that abDGCs constitute a subset of high-firing-rate neurons with enhanced activity responses to novelty and strong modulation by theta oscillations. Selectively activating abDGCs in their 4–7-week post-birth period increases sparsity of hippocampal population patterns, whereas suppressing abDGCs reduces this sparsity, increases principal cell firing rates and impairs novel object recognition with reduced dimensionality of the network firing structure, without affecting single-neuron spatial representations. We propose that adult-born granule cells transiently support sparser hippocampal population activity structure for higher-dimensional responses relevant to effective mnemonic information processing.

DOI: 10.1038/s41593-022-01176-5

Source: https://www.nature.com/articles/s41593-022-01176-5