Vestibular Contributions to Head Direction Cells

描述（由申请人提供）：大鼠和栗鼠大脑的几个区域的神经元编码动物头部面对的当前方向。这些“头向”（HD）细胞的活动在前庭周围病变后被取消，但负责产生和维持HD信号的电路尚未建立。这项建议的目的是为了更好地了解前庭系统和HD细胞活性之间的关系。特异性目的1验证了栗鼠的水平半规管是正常HD细胞活动所必需的假设。如果水平半规管对高清信号的产生至关重要，那么堵塞这些半规管将会干扰高清信号。特异性目的2验证了吻侧下舌前核（NPH）的神经活动包括可能支持下游HD细胞活动的信号的假设。吻侧NPH接收来自前庭核的输入，并投射到背侧被盖核（DTN），在那里发现了角头速度信号。特异性目的3验证了NPH中投射到DTN的细胞与向外展核提供输入的NPH细胞不同的假设。这将确定NPH眼动信号是否有助于高清信号。

DESCRIPTION (provided by applicant): Neurons in several areas of the rat and chinchilla brain encode the current direction that the animal's head faces. The activity of these "head direction" (HD) cells is abolished following peripheral vestibular lesions, but the circuitry responsible for generating and maintaining the HD signal has not been established. The purpose of this proposal is to better understand the relationship between the vestibular system and HD cell activity. Specific Aim 1 tests the hypothesis that horizontal semicircular canals in the chinchilla are necessary for normal HD cell activity. If the horizontal semicircular canals are essential for generation of the HD signal, then plugging those canals will disrupt the HD signal. Specific Aim 2 tests the hypothesis that neural activity in the rostral nucleus prepositus hypoglossi (NPH) includes signals that could support HD cell activity found downstream. The rostral NPH receives input from vestibular nuclei and projects to dorsal tegmental nucleus (DTN), where angular head velocity signals have been found. Specific Aim 3 tests the hypothesis that cells in NPH that project to the DTN are distinct from NPH cells that provide input to the abducens nucleus. This will establish whether NPH eye movement signals could contribute to the HD signal.