近日，美国麻省理工学院Mehrdad Jazayeri团队揭示灵长类动物内嗅皮层的心理导航。该研究于2024年6月12日在线发表于国际一流学术期刊《自然》。

研究人员检验了最初认知图谱理论的一个基本假设：认知图谱支持内源计算，而无需外部输入。在一项心理导航任务中，研究人员记录了猴子内嗅皮层的数据，该任务要求猴子在没有看到中间地标的情况下使用操纵杆在一对视觉地标之间产生一维向量。这些猴子能够完成这项任务并将其推广到新的视觉对，这表明它们依赖于对地标的结构化表征。任务调制神经元表现出与地标的时间结构相匹配的周期性和斜坡性，并显示出连续吸引子网络的特征。路径整合的连续吸引子网络模型与赫布样的学习机制相结合，解释了该系统如何能够内源地回忆地标。

该模型还做出了一个出乎意料的预测，即内源性地标会暂时减缓路径整合，重置动力学，从而降低变异性。这一预测在对发射率变异性和行为的重新分析中得到了证实。这些研究结果将内嗅皮层的结构化活动模式与心理导航过程中认知地图的内源招募联系起来。

研究人员表示，认知地图是一种结构适当的表征，可以利用以往的经验进行新的计算，例如在熟悉的空间中规划新的路线。在哺乳动物身上进行的研究发现，在空间和非空间领域的外源感官输入情况下，都有这种表征的直接证据。

附：英文原文

Title: Mental navigation in the primate entorhinal cortex

Author: Neupane, Sujaya, Fiete, Ila, Jazayeri, Mehrdad

Issue&Volume: 2024-06-12

Abstract: A cognitive map is a suitably structured representation that enables novel computations using previous experience; for example, planning a new route in a familiar space1. Work in mammals has found direct evidence for such representations in the presence of exogenous sensory inputs in both spatial2,3 and non-spatial domains4,5,6,7,8,9,10. Here we tested a foundational postulate of the original cognitive map theory1,11: that cognitive maps support endogenous computations without external input. We recorded from the entorhinal cortex of monkeys in a mental navigation task that required the monkeys to use a joystick to produce one-dimensional vectors between pairs of visual landmarks without seeing the intermediate landmarks. The ability of the monkeys to perform the task and generalize to new pairs indicated that they relied on a structured representation of the landmarks. Task-modulated neurons exhibited periodicity and ramping that matched the temporal structure of the landmarks and showed signatures of continuous attractor networks12,13. A continuous attractor network model of path integration14 augmented with a Hebbian-like learning mechanism provided an explanation of how the system could endogenously recall landmarks. The model also made an unexpected prediction that endogenous landmarks transiently slow path integration, reset the dynamics and thereby reduce variability. This prediction was borne out in a reanalysis of firing rate variability and behaviour. Our findings link the structured patterns of activity in the entorhinal cortex to the endogenous recruitment of a cognitive map during mental navigation.

DOI: 10.1038/s41586-024-07557-z

Source: https://www.nature.com/articles/s41586-024-07557-z