Vestibulocerebellar function in channelopathy mutants

小脑是神经回路的重要组成部分，在头部运动时稳定眼睛，小脑的紊乱会导致视力下降。其具体的计算作用仍有争议，但其功能的关键可能在于其神经元的独特结构和电导在进化过程中被高度保存。研究改变这种保守特征的影响将有助于深入了解它们所支持的计算过程。这种方法现在是可行的，因为遗传学和分子生物学的研究已经确定了小鼠品系中p型钙通道的突变，p型钙通道集中在小脑中，在定义浦肯野细胞的电生理特性中起着关键作用。本项目将描述p通道突变小鼠的眼运动异常，并使用神经元记录来证明这些异常与小脑信号处理紊乱有关。特异性目标1和2将验证突变株中代偿性眼球运动（如前庭眼反射，VOR）的动态和空间特征紊乱的假设。特异性目标3将测试突变体在改变VOR增益或方向的能力方面具有特异性缺陷的假设。总之，具体目标1-3将确定一组适合后续电生理技术调查的异常。具体目标4将通过测试下橄榄（也表达p通道）功能障碍可以作为突变体眼部异常的来源消除的假设来启动电生理学研究。钙通道突变与家族性偏头痛和发作性共济失调等人类疾病有关。因此，这项研究产生的对正常小脑功能的见解也应该促进我们对遗传性神经系统疾病机制的理解。

The cerebellum is a critical component of the neural circuitry that stabilizes the eyes during head movements, and disorders of the cerebellum uniformly degrade vision. Its exact computational role remains controversial, but a key to its function may lie in the high degree to which the unique architecture and conductances of its neurons have been conserved though evolution. Studying the effects of altering this conserved features would give insight into the computational processes they support. This approach is now feasible, as research in genetics and molecular biology has identified mouse strains harboring mutations in the P-type calcium channel, which is concentrated in the cerebellum and plays a key role in defining the electrophysiological characteristics of the Purkinje cell. This project will characterize the ocular motor abnormalities of mice with P-channel mutations, and use neuronal recordings to prove that these abnormalities are referable to disordered cerebellar signal processing. Specific Aim 1 and 2 will test the hypothesis that the dynamic and spatial characteristics of compensatory eye movements (such as vestibulo-ocular reflex, VOR), are disordered in the mutant strains. Specific aim 3 will test the hypothesis that mutants have specific deficits in the ability to alter the gain or direction of the VOR. Together, specific aims 1-3 will identify a set of abnormalities suitable for subsequent investigation with electrophysiological techniques. Specific aim 4 will initiate the electrophysiological investigation by testing the hypothesis that dysfunction in the inferior olive (which also expressed the P-channel) can be eliminated as a source of the mutants' ocular abnormalities. Calcium channel mutations have been implicated in human diseases such as familial migraine and episodic ataxia. Thus, the insights into normal cerebellar function generated by this study should also advance our understanding of mechanisms of heritable neurological disease.