Trained slow tracking. II. Bidirectional discharge patterns of cerebellar nuclear, motor cortex, and spindle afferent neurons.
Trained slow tracking. II. Bidirectional discharge patterns of cerebellar nuclear, motor cortex, and spindle afferent neurons.
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训练有素的慢速追踪。
DOI：
10.1152/jn.1985.54.5.1228
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发表时间：
1985
影响因子：
2.5
通讯作者：
ThachJr,WT
中科院分区：
文献类型：
--
作者：
Schieber,MH;ThachJr,WT
在训练、慢持-斜持-持跟踪、快速交替运动、扭矩-脉冲扰动和动作性震颤时，在猴子手腕的齿状核和中间小脑核、运动皮质、C7和C8背根神经节记录了单单元放电。在两只猴子中发现了57个齿状神经元和45个插入神经元，这些神经元与慢速跟踪运动有关。几乎所有的神经元都有一个明显的双向放电模式，包括在运动开始时或之前放电频率的突然增加（或减少），这种模式在整个斜坡中保持不同，与运动方向无关。在这项任务的执行过程中，没有一个神经元显示出与方向、位置、速度或负载的明确关系。然而，这些神经元中的许多放电与快速交替和（对于间位）扭矩脉冲有关，其模式是方向上的相互作用。部分间位神经元表现出与震颤相关的调制叠加在与慢速斜坡相关的双向放电上。在慢持-斜持-慢持跟踪过程中，29个运动皮层神经元以两种模式放电。第一类神经元（29个中的14个）在相反方向的运动中表现出逐渐变化的、方向上的反向调节的放电频率。这些神经元通常与扭矩负荷和/或手腕位置有关，但与速度无关。放电模式与前臂肌肉的活动模式相似。II类神经元（29个中的15个）表现出放电频率的突变，这种突变是双向的。它们通常与扭矩负载和/或速度有关，而与位置无关。运动皮层神经元的放电与快速交替运动、扭矩脉冲和震颤有关，其模式相似，无法区分这两类。背根神经节中有5个单位被确定为肌纺锤体传入。在斜坡过程中，它们的放电模式是双向的，与运动皮层（II类）和小脑神经元的双向放电模式相似。对于一些细胞，双向模式与运动的方向和速度以及扭矩负荷的大小有关，但与手腕位置（肌肉长度）的大变化无关。与震颤有关的调制叠加在与斜坡有关的双向模式上。纺锤体传入放电与母肌同步肌电图（EMG）的比较表明，纺锤体是由与相同的α -骨骼运动神经元分离的γ -融合运动活动驱动的。（摘要删节为400字）
Single-unit discharge was recorded in the dentate and interposed cerebellar nuclei, motor cortex, and C7 and C8 dorsal root ganglia during trained, slow hold-ramp-hold tracking, rapid alternating movement, torque-pulse perturbation, and action tremor of the monkey's wrist. Fifty-seven dentate and 45 interposed neurons were found in two monkeys that discharged in relation to slow tracking movement. Nearly all neurons had a distinct bidirectional pattern of discharge consisting of an abrupt increase (or decrease) in firing frequency at or before the onset of movement that was variably maintained throughout the ramp and was independent of movement direction. None of the neurons showed a clear relationship to direction, position, velocity, or load during the performance of this task. Nevertheless, many of these neurons discharged in relation to rapid alternation and (for interpositus) torque pulses in patterns that were directionally reciprocal. Some interpositus neurons showed a modulation related to tremor superimposed on the bidirectional discharge related to slow ramps. Twenty-nine neurons in motor cortex of one monkey discharged during slow hold-ramp-hold tracking in two patterns. Class I neurons (14 of 29) showed gradually changing, directionally reciprocal modulations of firing frequency for movements in opposite directions. These neurons were often related to torque load and/or to wrist position but not to velocity. The discharge pattern was similar to the pattern of activity of forearm muscles. Class II neurons (15 of 29) showed an abrupt change in firing frequency that was bidirectional. They were often related to torque load and/or to velocity but not to position. Motor cortex neurons discharged in relation to rapid alternating movements, torque pulses, and tremor in similar patterns that did not distinguish the two classes. Five units in dorsal root ganglia were identified as muscle spindle afferents. During ramps, their pattern of discharge was bidirectional and resembled the bidirectional discharge patterns of neurons in motor cortex (class II) and cerebellum. For some cells the bidirectional pattern varied slightly in relation to the direction and velocity of movement and the amount of torque load, but it was not related to the large changes in wrist position (muscle length). Modulation in relation to tremor was superimposed on the bidirectional pattern related to ramps. The comparison of spindle afferent discharge with the concurrent electromyogram (EMG) of the parent muscle suggested that spindles were driven by gamma-fusimotor activity dissociated from that of homonymous alpha-skeletomotor neurons.(ABSTRACT TRUNCATED AT 400 WORDS)