Changes in the temporal pattern of primary motor cortex activity in a directional isometric force versus limb movement task
Changes in the temporal pattern of primary motor cortex activity in a directional isometric force versus limb movement task
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DOI：
10.1152/jn.1998.80.3.1577
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发表时间：
1998-09-01
影响因子：
2.5
通讯作者：
Kalaska, JF
中科院分区：
文献类型：
--
作者：
Sergio, LE;Kalaska, JF
我们记录了75个近臂相关细胞在尾侧初级运动皮层（MI）的活动，而猴子产生的等距力或肢体运动对惯性负载。力和运动在水平面上的八个方向上。在手部产生的等长力在目标力水平的方向上单调增加。在运动任务中对负载施加的力更复杂，包括在运动期间当手接近目标时的瞬时减速阶段。近臂肌肉的肌电图（EMG）活动反映了动力学的任务依赖性变化，在等长任务和运动任务中的相互三相爆发模式期间，活动呈斜坡增加。滑动50毫秒的窗口分析表明，方向性的肌电图，在手为中心的空间坐标表示时，保持稳定的整个等长斜坡，但往往表现出显着的瞬态转变，在肢体运动。M1中的许多细胞在两种任务之间的活动模式和瞬时方向性表现出相应的显着变化。这种瞬时解离的放电从手位移的方向运动学的证据表明，许多单个近端臂相关的M1细胞的活动不仅耦合到手运动的方向和速度。
We recorded the activity of 75 proximal-arm-related cells in caudal primary motor cortex (MI) while a monkey generated either isometric forces or limb movements against an inertial load. The forces and movements were in eight directions in a horizontal plane. The isometric force generated at the hand increased monotonically in the direction of the target force level. The force exerted against the load in the movement task was more complex, including a transient decelerative phase during the movement as the hand approached the target. Electromyographic (EMG) activity of proximal-arm muscles reflected the task-dependent changes in dynamics, showing a ramp increase in activity during the isometric task and a reciprocal triphasic burst pattern in the movement task. A sliding 50-ms window analysis showed that the directionality of the EMG, when expressed in hand-centered spatial coordinates, remained stable throughout the isometric ramp but often showed a significant transient shift during the limb movements. Many cells in M1 showed corresponding significant changes in activity pattern and instantaneous directionality between the two tasks. This momentary dissociation of discharge from the directional kinematics of hand displacement is evidence that the activity of many single proximal-arm related M1 cells is not coupled only to the direction and velocity of hand motion.