美国霍华德·休斯医学研究所Albert K. Lee、Sandro Romani和Jae Sung Lee团队近日取得一项新成果。他们揭示了海马空间代码随时间、环境和价值观变化的统计结构。这一研究成果在线发表在2020年10月8日的《细胞》上。

在小鼠中使用纵向钙离子成像、多样的环境模拟和不同的奖励机制，研究人员得到了一个统一的CA1表征概率模型。每个单元的倾向性决定了每个单元空间具有多少个场所，预测其与奖励有关的活动，并可以在不同的环境中保存数月之久。倾向性广泛分布——许多细胞具有低倾向性而一些细胞具有高倾向性——因此剧烈影响了海马的表征。这导致从稀疏到密集的一系列空间代码。

相邻细胞之间的倾向以独特的方式变化约10倍，表明某一预测细胞类型在功能上存在实质性差异。细胞内记录将倾向与细胞兴奋性联系起来。每个细胞在不同条件下的倾向稳定性表明该基本特性具有解剖学、转录和/或发育起源。

据悉，海马体活动表征了许多行为上重要的变量，例如环境、给定环境中动物的位置、时间和奖励。

附：英文原文

Title: The Statistical Structure of the Hippocampal Code for Space as a Function of Time, Context, and Value

Author: Jae Sung Lee, John J. Briguglio, Jeremy D. Cohen, Sandro Romani, Albert K. Lee

Issue&Volume: 2020-10-08

Abstract: Hippocampal activity represents many behaviorally important variables, including context,an animal’s location within a given environmental context, time, and reward. Usinglongitudinal calcium imaging in mice, multiple large virtual environments, and differingreward contingencies, we derived a unified probabilistic model of CA1 representationscentered on a single feature—the field propensity. Each cell’s propensity governshow many place fields it has per unit space, predicts its reward-related activity,and is preserved across distinct environments and over months. Propensity is broadlydistributed—with many low, and some very high, propensity cells—and thus stronglyshapes hippocampal representations. This results in a range of spatial codes, fromsparse to dense. Propensity varied ～10-fold between adjacent cells in salt-and-pepperfashion, indicating substantial functional differences within a presumed cell type.Intracellular recordings linked propensity to cell excitability. The stability ofeach cell’s propensity across conditions suggests this fundamental property has anatomical,transcriptional, and/or developmental origins.

DOI: 10.1016/j.cell.2020.09.024

Source: https://www.cell.com/cell/fulltext/S0092-8674(20)31165-X