三维空间中头方向细胞的计算建模：方向编码与视觉线索操控

文献信息

中文摘要

头方向（HD）细胞能够根据动物头部方位角方向选择性放电，并形成用于导航的内部罗盘。它们被发现于包括背侧前下托和内嗅皮层在内的哺乳动物边缘系统中。其 underlying 网络以自组织方式更新方向估计，并可由外部感觉线索重新校准。尽管环形吸引子模型被提出用于解释水平平面上的方位角编码，但它们无法解释在三维（3-D）空间中导航的飞行蝙蝠前下托 HD 细胞中观察到的方位角-俯仰角联合调谐。基于 3-D 电生理记录，我们开发了一个环面连续吸引子网络，联合编码头部方向的水平方位角和垂直俯仰角。该模型能够再现单个 HD 细胞的实验记录调谐曲线，并通过 HD 细胞群体准确编码蝙蝠的方位角-俯仰角动态头部方向。该模型还模拟了水平视觉线索操控对 3-D 空间中 HD 系统的影响，并预测水平地标旋转如何诱导一种在线索移除后持续存在的方位角偏移，这与二维实验发现相当。这项研究阐明了联合 3-D 方向编码如何由前庭输入、视觉信息和循环连接产生和修改。它还揭示了真实 3-D 环境中大脑导航功能的计算原理和特性，并为未来研究提供了新的理论参考。

英文摘要

Head direction (HD) cells can fire selectively as a function of the animal's head azimuth direction and form an internal compass for navigation. They were found in the mammalian limbic system including the dorsal presubiculum and entorhinal cortex. The underlying network updates its directional estimate in a self-organized fashion and can be recalibrated by external sensory cues. Although ring-attractor models were proposed to account for azimuth coding on horizontal planes, they cannot explain conjunctive azimuth-and-pitch tuning observed in HD cells of the presubiculum of flying bats navigating in three-dimensional (3-D) space. Based on the 3-D electrophysiological recordings, we developed a toroidal continuous attractor network that jointly encodes horizontal azimuth and vertical pitch angle of head direction. The model can reproduce the experimentally recorded tuning curves of individual HD cells, and accurately encode the azimuth-pitch dynamic head direction of bat by HD cell population. The model also simulate the influence of horizontal visual cue manipulation on the HD system in 3-D space and predicts how horizontal landmark rotation induces a sustained azimuthal offset that persists after the cue is removed, which is comparable to two-dimensional experimental findings. This research clarifies how conjunctive 3-D direction codes are generated and modified by vestibular input, visual information and recurrent connectivity. It also uncovers the computational principles and properties of the brain's navigation functions in realistic 3-D environments and offers new theoretical reference for future studies.