Vestibular Contributions to Head Direction Cells

描述（由申请人提供）：大鼠和栗鼠大脑几个区域的神经元编码动物头部面对的电流方向。这些“头部方向”（HD）细胞的活动在外周前庭病变后被消除，但负责产生和维持HD信号的电路尚未建立。该建议的目的是更好地了解前庭系统和HD细胞活动之间的关系。具体目标1测试的假设，水平半规管在灰鼠是必要的正常HD细胞的活动。如果水平半规管对于HD信号的产生是必不可少的，那么堵塞这些半规管将破坏HD信号。具体目标2测试的假设，即在吻侧核前置舌下（NPH）的神经活动包括信号，可以支持HD细胞的活动发现下游。头端NPH接受来自前庭核的输入并投射到背侧被盖核（DTN），在那里已经发现了头角速度信号。具体目标3检验了NPH中投射到DTN的细胞与向展神经核提供输入的NPH细胞不同的假设。这将确定NPH眼动信号是否可以对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.