Vestibulo-cerebellar contribution to spatial adaptation

描述（由申请人提供）：我们提出了三个研究领域，以了解前庭小脑的电路如何使用前庭信息来修改浦肯野细胞的简单尖峰（SS）输出，以及这种输出如何促进前庭定向改变的行为适应：1)将前庭信息传递到下橄榄的电路。副孤核（Psol）将前庭信号传递给下橄榄的两个亚核- β核和背内侧细胞柱（dmcc）。单侧Psol病变减少，但不消除对侧小舌结节的前庭调节攀爬纤维反应（CFRs），这意味着通往下橄榄的另一种突触前前庭通路。y群可能是这种替代途径的起源。我们将把逆行和正行示踪剂与单个y组神经元的记录结合起来，以确定它们携带的前庭和光动力学信号的类型。2)结缔组织CFR-SS前庭可塑性，了解攀爬纤维与平行纤维在浦肯野细胞上的相互作用对了解小脑至关重要。相互作用会产生短期或长期的后果。我们将在体内电刺激平行纤维和攀爬纤维，以便它们的相互作用可以根据已知的前庭电路来解释。来自β核中已知半规管区的攀爬纤维截击将与来自单个垂直半规管的平行纤维截击相互作用。这些相互作用揭示了攀爬纤维地形如何反映在浦肯野细胞输出中。3)小舌结节在前庭-眼反射空间定向动态控制中的作用行为评价。兔绕纵轴旋转可调节先前诱导的眼震后光动力学（OKAN II）的速度和方向。眼球震颤速度降低的意义以及结节对眼球速度改变的可能贡献尚不清楚。我们认为，头部倾斜会导致眼球震颤速度的降低，从而减少所有眼睛反射的增加，这些反射与感知到的垂直方向或先前“记忆”的方向相冲突。我们将测量在双侧小舌结节破坏前后，当兔头的方向导致眼球震颤时，在眼眶内以不同角度进行慢相速度的变化。

DESCRIPTION (provided by applicant): We propose three areas of investigation to understand how the circuitry of the vestibulocerebellum uses vestibular information to modify the simple spike (SS) output of Purkinje cells and how this output contributes to behavioral adaptation to altered vestibular orientation: 1) Circuitry transmitting vestibular information to inferior olive. The parasolitary nucleus (Psol) conveys vestibular signals to the beta-nucleus and dorsomedial cell column (dmcc), two subnuclei of the inferior olive. Unilateral lesions of Psol reduce, but do not eliminate vestibularly-modulated climbing fiber responses (CFRs) in the contralateral uvula-nodulus, implying an alternative presynaptic vestibular pathway to the inferior olive. The Y-group may be the origin of this alternative pathway. We will combine retrograde and orthograde tracers with recordings from single Y-group neurons to determine the types of vestibular and optokinetic signals carried by them. 2) Conjunctive CFR-SS vestibular plasticity in the nodulus, understanding interactions between climbing and parallel fibers on Purkinje cells is critical to understanding the cerebellum. Interactions occur with short- or long-term consequences. We will electrically stimulate parallel and climbing fibers in vivo so that their interactions can be interpreted in terms of known vestibular circuitry. A climbing fiber volley from a known semicircular canal zone in the beta-nucleus, will be interacted with a parallel fiber volley from a single vertical semicircular canal. These interactions should reveal how climbing fiber topography is reflected in Purkinje cell output. 3) Behavioral evaluation of the role of the uvula-nodulus in the dynamic control of vestibule-ocular reflex orientation in space. Rotation of rabbits about a longitudinal axis modulates the velocity and orientation of a previously induced optokinetic afternystagmus (OKAN II). The significance of decreases in nystagmus velocity and the possible contribution of the nodulus to modification of eye velocity are poorly understood. We suggest that head tilt induces a reduction in nystagmus velocity to reduce the gain of all eye reflexes that conflict perceived vertical orientation or a previously "remembered" orientation. We will measure changes in slow phase velocity when the orientation of the rabbit's head causes nystagmus to be executed at different angles within the orbit before and after bilateral destruction of the uvula-nodulus.