Department of Psychological Brain Sciences, Dartmouth College, Dartmouth, New Hampshire 03755.
Department of Psychological Brain Sciences, Dartmouth College, Dartmouth, New Hampshire 03755
J Neurosci. 2023 Dec 6;43(49):8403-8424. doi: 10.1523/JNEUROSCI.0581-23.2023.
The sense of orientation of an animal is derived from the head direction (HD) system found in several limbic structures and depends on an intact vestibular labyrinth. However, how the vestibular system influences the generation and updating of the HD signal remains poorly understood. Anatomical and lesion studies point toward three key brainstem nuclei as key components for generating the HD signal-nucleus prepositus hypoglossi, supragenual nucleus, and dorsal paragigantocellularis reticular nuclei. Collectively, these nuclei are situated between the vestibular nuclei and the dorsal tegmental and lateral mammillary nuclei, which are thought to serve as the origin of the HD signal. To determine the types of information these brain areas convey to the HD network, we recorded neurons from these regions while female rats actively foraged in a cylindrical enclosure or were restrained and rotated passively. During foraging, a large subset of cells in all three nuclei exhibited activity that correlated with the angular head velocity (AHV) of the rat. Two fundamental types of AHV cells were observed; (1) symmetrical AHV cells increased or decreased their firing with increases in AHV regardless of the direction of rotation, and (2) asymmetrical AHV cells responded differentially to clockwise and counterclockwise head rotations. When rats were passively rotated, some AHV cells remained sensitive to AHV, whereas firing was attenuated in other cells. In addition, a large number of AHV cells were modulated by linear head velocity. These results indicate the types of information conveyed from the vestibular nuclei that are responsible for generating the HD signal. Extracellular recording of brainstem nuclei (nucleus prepositus hypoglossi, supragenual nucleus, and dorsal paragigantocellularis reticular nucleus) that project to the head direction circuit identified different types of AHV cells while rats freely foraged in a cylindrical environment. The firing of many cells was also modulated by linear velocity. When rats were restrained and passively rotated, some cells remained sensitive to AHV, whereas others had attenuated firing. These brainstem nuclei provide critical information about the rotational movement of the head of the rat in the azimuthal plane.
动物的方向感源自于几个边缘结构中发现的头部方向（HD）系统，该系统依赖于完整的前庭迷路。然而，前庭系统如何影响 HD 信号的产生和更新仍知之甚少。解剖学和损伤研究指出，三个关键的脑干核是产生 HD 信号的关键组成部分——舌下前核、上核和背侧巨细胞网状核。这些核一起位于前庭核与背侧被盖和外侧乳头体核之间，被认为是 HD 信号的起源。为了确定这些脑区向 HD 网络传递的信息类型，我们在雌性大鼠主动在圆柱形围栏中觅食或被动约束和旋转时，从这些区域记录神经元。在觅食过程中，所有三个核中的大量细胞表现出与大鼠角头速度（AHV）相关的活动。观察到两种基本类型的 AHV 细胞；（1）对称 AHV 细胞无论旋转方向如何，随着 AHV 的增加而增加或减少其放电；（2）不对称 AHV 细胞对顺时针和逆时针头旋转的反应不同。当大鼠被动旋转时，一些 AHV 细胞仍然对 AHV 敏感，而其他细胞的放电则减弱。此外，大量 AHV 细胞被线性头速度调制。这些结果表明，从前庭核传递的负责产生 HD 信号的信息类型。当大鼠在圆柱形环境中自由觅食时，对投射到头部方向回路的脑干核（舌下前核、上核和背侧巨细胞网状核）进行细胞外记录，确定了不同类型的 AHV 细胞。许多细胞的放电也受到线性速度的调制。当大鼠被约束并被动旋转时，一些细胞仍然对 AHV 敏感，而其他细胞的放电则减弱。这些脑干核提供了关于大鼠在方位平面中头部旋转运动的关键信息。
