美国普林斯顿大学David W. Tank、Carlos D. Brody等研究人员合作揭示海马中抽象知识的几何结构。2021年6月16日，《自然》杂志在线发表了这一最新研究成果。
研究人员使用双光子钙成像显示了背海马体中的单个神经元联合编码累积证据与空间位置的小鼠在虚拟现实中执行决策任务。非线性降维表明，大约4到6个潜在变量可以很好地描述种群活动，这表明神经活动仅限于低维流形。在这个低维空间中，物理变量和抽象变量以有序的方式联合映射，并创建了一个几何表示，研究人员在小鼠中展示了相似的结果。联合认知地图的存在表明海马体执行一般计算——创建包含所学知识的几何表示的特定于任务的低维流形。
据介绍，海马神经元编码物理变量 ，例如认知地图中的空间或听觉频率。此外，人类的功能磁共振成像研究表明，海马体还可以编码更抽象的、学习到的变量。然而，它们与物理变量的现有神经表征的整合是未知的。
附：英文原文
Title: Geometry of abstract learned knowledge in the hippocampus
Author: Edward H. Nieh, Manuel Schottdorf, Nicolas W. Freeman, Ryan J. Low, Sam Lewallen, Sue Ann Koay, Lucas Pinto, Jeffrey L. Gauthier, Carlos D. Brody, David W. Tank
Issue&Volume: 2021-06-16
Abstract: Hippocampal neurons encode physical variables1,2,3,4,5,6,7 such as space1 or auditory frequency6 in cognitive maps8. In addition, functional magnetic resonance imaging studies in humans have shown that the hippocampus can also encode more abstract, learned variables9,10,11. However, their integration into existing neural representations of physical variables12,13 is unknown. Here, using two-photon calcium imaging, we show that individual neurons in the dorsal hippocampus jointly encode accumulated evidence with spatial position in mice performing a decision-making task in virtual reality14,15,16. Nonlinear dimensionality reduction13 showed that population activity was well-described by approximately four to six latent variables, which suggests that neural activity is constrained to a low-dimensional manifold. Within this low-dimensional space, both physical and abstract variables were jointly mapped in an orderly manner, creating a geometric representation that we show is similar across mice. The existence of conjoined cognitive maps suggests that the hippocampus performs a general computation—the creation of task-specific low-dimensional manifolds that contain a geometric representation of learned knowledge.
DOI: 10.1038/s41586-021-03652-7
Source: https://www.nature.com/articles/s41586-021-03652-7
Nature：《自然》，创刊于1869年。隶属于施普林格·自然出版集团，最新IF：69.504
官方网址：http://www.nature.com/
投稿链接：http://www.nature.com/authors/submit_manuscript.html
本期文章：《自然》：Online/在线发表
