원숭이 대뇌 운동전야피질 신경세포의 Movement Field에 관한 연구 = Movement Fields of Neurons in the Premotor Cortex of the Primate

다국어 초록 (Multilingual Abstract)

This study evaluated the representation of horizontal, two dimensional movements in the premotor cortex of the primate, emphasizing the characteristics of the movement fields of these cells. Starting from a central start zone three macaca mulatta monkeys were required to move to one of 30 randomly presented target zones displayed on a computer controlled, horizontally positioned video screen using a draftsman's arm style manipulandum. A cursor was projected on the video screen and provided real time visual update of the animal's position. The task required placing the cursor within the start zone and target boxes. Target zones were arranged in five sets of equally spaced targets (60˚) around a central start zone, each set at a different distance. Chronic unit recording techniques were used to record the activities of 238 premotor cortical neurons before and during this task. In addition to recording the position of the hand(manipulandum position) and features of trajectory kinematics in the horizontal plane, chronic EMC electrodes were used to monitor shoulder and forearm EMG activity. Horizontal and vertical eye movements were monitored using an infrared oculometer. Three dimensional plots of the cells' firing rate above background for the discharge prior to(premovement component) and after the onset of movement (movement component) were constructed. Premotor cortical cells which increased their discharge prior to or during the task showed a preferential modulation for a specific region(direction and amplitude) of horizontal extrapersonal space in which the movement was made.
Although the extent of the movement field could be large, the discharge was clearly restricted to a region of the horizontal work space. Also the movement fields exhibited a distinct center where the discharge was maximal. In most cells both the premovement and ~movement components increased over the same region of horizontal space. In the group of cells the modulation was dependent on the movement origin. These preliminary observations on the characteristics of the movement fields of premotor cortical neurons raise the intriguing possibility that aspects of extrapersonal space could well be represented in the discharge of these cells.