Role of the cerebellum in reaching movements in humans. II. A neural model of the intermediate cerebellum
Role of the cerebellum in reaching movements in humans. II. A neural model of the intermediate cerebellum
复制标题
DOI：
10.1046/j.1460-9568.1998.00007.x
复制
发表时间：
1998-01-01
影响因子：
3.4
通讯作者：
Kawato, M
中科院分区：
文献类型：
--
作者：
Schweighofer, N;Spoelstra, J;Kawato, M
小脑是控制多关节运动的关键，当小脑受损时，操作误差大于单个关节产生的总和误差。在这篇论文(Schweighofer等人，1998)中，提出了视觉引导手臂运动的功能解剖学模型。该模型包括一个具有实际传输时延的基本前馈/反馈控制器，并连接到一个两连杆、六肌肉的平面手臂。在目前的研究中，我们通过在这个功能控制模型中嵌入一个新颖的、详细的小脑神经网络来研究小脑在伸展运动中的作用。我们可以获得真实的小脑输入，并评估小脑在学习控制手臂方面的作用，这个小脑网络学习了基本前馈/反馈控制器没有提供的手臂逆动力学部分。尽管劣质橄榄的发火率和嘈杂的苔藓纤维输入非常低，但该模型可以减少预期动作和计划动作之间的误差。不同细胞组的反应与生物细胞组的反应相当。特别是，被建模的浦肯野细胞在学习后表现出定向调谐，由于它们的长度，平行的纤维为浦肯野细胞提供了这一协调任务所需的输入。下橄榄反应包含两个不同的成分；锁定于运动开始的早期反应总是存在的，而后者在学习后消失。这些结果支持小脑参与运动学习的理论。
The cerebellum is essential for the control of multijoint movements; when the cerebellum is lesioned, the performance error is more than the summed errors produced by single joints. In the companion paper (Schweighofer et al., 1998), a functional anatomical model for visually guided arm movement was proposed. The model comprised a basic feedforward/feedback controller with realistic transmission delays and was connected to a two-link, six-muscle, planar arm. In the present study, we examined the role of the cerebellum in reaching movements by embedding a novel, detailed cerebellar neural network in this functional control model. We could derive realistic cerebellar inputs and the role of the cerebellum in learning to control the arm was assessed,This cerebellar network learned the part of the inverse dynamics of the arm not provided by the basic feedforward/feedback controller. Despite realistically low inferior olive firing rates and noisy mossy fibre inputs, the model could reduce the error between intended and planned movements. The responses of the different cell groups were comparable to those of biological cell groups. In particular, the modelled Purkinje cells exhibited directional tuning after learning and the parallel fibres, due to their length, provide Purkinje cells with the input required for this coordination task. The inferior olive responses contained two different components; the earlier response, locked to movement onset, was always present and the later response disappeared after learning. These results support the theory that the cerebellum is involved in motor learning.