Vestibular Contributions to Head Direction Cells

描述(申请人提供)：大鼠和栗鼠大脑几个区域的神经元编码动物头部当前面对的方向。外周前庭损伤后，这些“头向”(HD)细胞的活动被取消，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细胞活动之间的关系。特定目的1验证了栗鼠水平半规管是正常HD细胞活动所必需的假说。如果水平半规管对于HD信号的产生是必不可少的，那么堵塞这些管道将会干扰HD信号。特定目标2测试假设，即嘴核舌下前置核(NPH)的神经活动包括可能支持下游发现的HD细胞活动的信号。吻侧NPH接受前庭核团的输入，投射到被盖背核(DTN)，在那里发现了头部的角速度信号。特定目标3测试了这样的假设，即NPH中投射到DTN的细胞不同于向外展神经核提供输入的NPH细胞。这将确定NPH眼球运动信号是否对HD信号有贡献。

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.