Fu Q G, Flament D, Coltz J D, Ebner T J
Department of Neurosurgery, University of Minnesota, Minneapolis 55455, USA.
J Neurophysiol. 1997 Jul;78(1):478-91. doi: 10.1152/jn.1997.78.1.478.
The simple spike discharge of 231 cerebellar Purkinje cells in ipsilateral lobules V and VI was recorded in three monkeys trained to perform a visually guided reaching task requiring movements of different directions and distances. The discharge of 179 cells was significantly modulated during movement to one or more targets. Mean simple spike rate was fitted to a cosine function for direction tuning, a simple linear function for distance modulation, and a multiple linear regression model that included terms for direction, distance, and target position. On the basis of the fit to the direction and distance models, there were more distance-related than direction-related Purkinje cells. The simple spike discharge of most direction-related cells modulated at only one target distance. The preferred directions for the simple spike tuning were not uniformly distributed across the workspace. The discharge of most distance-related cells modulated along only one movement direction. On the basis of the multiple linear regression model, simple spike discharge was also correlated with target position, in addition to direction and distance. Approximately half of the Purkinje cells had simple spike activity associated with only a single parameter, and only a small fraction of the cells with all three. The multiple regression model was extended to evaluate the correlations as a function of time. Considerable overlap occurred in the timing of the simple spike correlations with the parameters. The latency for correlation with movement direction occurred mainly in a 500-ms interval centered on movement onset. The correlations with target position also occurred around movement onset, in the range of -200-500 ms. Distance correlations were more variable, with onset latencies from -500 to 1,000 ms. These results demonstrate that the simple spike discharge of cerebellar Purkinje cells is correlated with movement direction, distance, and target position. Comparing these results to motor cortical discharge shows that the correlations with these parameters were weaker in Purkinje cell simple spike discharge, and that, for the majority of Purkinje cells, the simple spike discharge was significantly related to only a single movement parameter. Other differences between simple spike responses and those of motor cortical cells include the nonuniform distribution of preferred directions and the extensive overlap in the timing of the correlations. These differences suggest that Purkinje cells process, encode, and use kinematic information differently than motor cortical neurons.
在三只经过训练以执行视觉引导伸手任务的猴子中，记录了同侧小叶V和VI中231个小脑浦肯野细胞的简单锋电位发放，该任务需要不同方向和距离的运动。在向一个或多个目标运动期间，179个细胞的发放受到显著调制。平均简单锋电位发放率针对方向调谐拟合为余弦函数，针对距离调制拟合为简单线性函数，并针对包括方向、距离和目标位置项的多元线性回归模型进行拟合。基于对方向和距离模型的拟合，与距离相关的浦肯野细胞比与方向相关的更多。大多数与方向相关的细胞的简单锋电位发放仅在一个目标距离处受到调制。简单锋电位调谐的首选方向在工作空间中并非均匀分布。大多数与距离相关的细胞的发放仅沿一个运动方向受到调制。基于多元线性回归模型，除了方向和距离外，简单锋电位发放还与目标位置相关。大约一半的浦肯野细胞的简单锋电位活动仅与单个参数相关，只有一小部分细胞与所有三个参数相关。多元回归模型被扩展以评估作为时间函数的相关性。简单锋电位相关性与参数的时间存在相当大的重叠。与运动方向相关的潜伏期主要出现在以运动开始为中心的500毫秒间隔内。与目标位置的相关性也出现在运动开始前后，范围为-200至500毫秒。距离相关性变化更大，起始潜伏期为-500至-1000毫秒。这些结果表明，小脑浦肯野细胞的简单锋电位发放与运动方向、距离和目标位置相关。将这些结果与运动皮层发放进行比较表明，浦肯野细胞简单锋电位发放中与这些参数的相关性较弱，并且对于大多数浦肯野细胞而言，简单锋电位发放仅与单个运动参数显著相关。简单锋电位反应与运动皮层细胞反应之间的其他差异包括首选方向的非均匀分布以及相关性时间的广泛重叠。这些差异表明，浦肯野细胞处理、编码和使用运动学信息的方式与运动皮层神经元不同。
