Does cerebellar cortex function as a forward internal model for motor control?

描述（由申请人提供）：运动控制理论家已经假设，产生快速，协调的运动需要控制电路，可以通过提供对运动命令产生的后果的估计来绕过感觉反馈延迟。这个控制元件被称为前向内部模型，它接收电机命令的传出副本和关于当前状态的信息，以预测肢体的未来状态（即位置和速度等运动学变量）。先前的心理物理、影像学和患者病例研究表明，小脑是实现内部模型的可能位置。然而，关于小脑神经元放电是否符合正向内模型的性质，电生理学研究很少。该项目的最终目的是评估小脑中/外侧区IV-VI小叶浦肯野细胞（PCs）的简单spike放电是否与前向内部模型的输出一致。虽然没有单一的结果可以最终证明这一假设，但两个研究恒河猴手部运动的电生理学实验被提出来测试一个正向内部模型的几个方面。目的1将检查PC射击是否以任务独立的方式预测未来的手部运动学。Aim 2将进一步评估模型的适应性，以及改变模型输入是否会改变预测的运动学。结果要么表明PC发射与正演模型的预期输出不兼容，要么为未来的实验提供坚实的支持。

DESCRIPTION (provided by applicant): Motor control theorists have postulated that production of rapid, coordinated movements requires control circuitry that can bypass sensory feedback delays by providing an estimate of the consequences resulting from a motor command. This control element, termed a forward internal model, receives an efferent copy of the motor command and information about the current state in order to predict the future state of the limb (i.e., kinematic variables like position and velocity). Previous psychophysical, imaging, and patient case studies suggest that the cerebellum is a possible location for implementation of an internal model. However, few electrophysiological studies have investigated whether the firing discharge from cerebellar neurons is consistent with the properties of a forward internal model. The ultimate goal of this project is to evaluate whether the simple spike firing from Purkinje cells (PCs) in lobules IV-VI of the intermediate/lateral cerebellar zones is consistent with output from a forward internal model. Although no single result will conclusively prove this hypothesis, two electrophysiology experiments examining hand movements in rhesus macaques are proposed to test several aspects of a forward internal model. Aim 1 will examine whether PC firing predicts future hand kinematics in a task-independent manner. Aim 2 will further evaluate model adaptability and whether changing model inputs alters predicted kinematics. The results will either show that PC firing is incompatible with the output expected from a forward model or provide solid support for future experiments. PUBLIC HEALTH RELEVANCE: An increased knowledge of healthy cerebellar function is essential for understanding how cerebellar brain injury or disease might manifest clinically and lead to deficits in motor coordination, learning, and movement timing. Recording activity from Purkinje cells, a specific type of neuron in the cerebellar cortex, during movement learning tasks may lead to increased understanding of how these cells act as a network to encode movement variables and learn new motor tasks. Perhaps most importantly, insights regarding the control parameters required for coordinated movements may lead to more specific rehabilitation therapies for patients with movement disorders and improved algorithms for controlling smart prosthetics.