Angelaki Dora E, Yakusheva Tatyana A
Department of Neurobiology, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
Ann N Y Acad Sci. 2009 May;1164:19-28. doi: 10.1111/j.1749-6632.2009.03939.x.
The peripheral vestibular system is faced by a sensory ambiguity, where primary otolith afferents respond identically to translational (inertial) accelerations and changes in head orientation relative to gravity. Under certain conditions, this sensory ambiguity can be resolved using extra-otolith cues, including semicircular canal signals. Here we review and summarize how neurons in the vestibular nuclei, rostral fastigial nuclei, cerebellar nodulus/uvula, and thalamus respond during combinations of tilt and translation. We focus primarily on cerebellar cortex responses, as nodulus/uvula Purkinje cells reliably encode translation rather than net gravito-inertial acceleration. In contrast, neurons in the vestibular and rostral fastigial nuclei, as well as the ventral lateral and ventral posterior nuclei of the thalamus represent a continuum, with some encoding translation and some net gravito-inertial acceleration. This review also outlines how Purkinje cells use semicircular canal signals to solve the ambiguity problem and how this solution fails at low frequencies. We conclude by attempting to bridge the gap between the proposed roles of nodulus/uvula in tilt/translation discrimination and velocity storage.
外周前庭系统面临着一种感觉模糊性，即初级耳石传入神经对平移（惯性）加速度以及头部相对于重力的方向变化的反应是相同的。在某些情况下，这种感觉模糊性可以通过包括半规管信号在内的耳石外线索来解决。在这里，我们回顾并总结了在前庭核、嘴侧顶核、小脑蚓小结/蚓垂和丘脑的神经元在倾斜和平移组合过程中的反应。我们主要关注小脑皮质的反应，因为蚓小结/蚓垂浦肯野细胞可靠地编码平移而非净重力惯性加速度。相比之下，前庭核和嘴侧顶核以及丘脑腹外侧核和腹后核中的神经元则呈现出一种连续状态，其中一些编码平移，一些编码净重力惯性加速度。本综述还概述了浦肯野细胞如何利用半规管信号来解决模糊性问题以及该解决方案在低频时是如何失效的。我们通过尝试弥合蚓小结/蚓垂在倾斜/平移辨别和速度存储方面所提出的作用之间的差距来得出结论。
