猴运动前区皮层神经元在顺序行为中的放电活动

NEURONAL ACTIVITY OF MONKEY DORSO-LATERAL PREMOTOR CORTEX DURING TASKS OF FIGURE RECOGNITION GUIDED MOTOR SEQUENCE VS MEMORIZED SPATIAL MOTOR SEQUENCE

本工作研究猴运动前区（PM）皮层神经元在视觉图形引导的有序运动行为（作者称之为FRS[1]）中的放电活动，并与在依靠记忆信息完成的空间顺序行为（MSS）中的活动作了比较。为此训练了三只猴同时学会FRS和MSS任务。对111个神经元的统计分析表明，它们在FRS和MSS暗示期中发生放电频率变化的均有一半以上，反应期里有放电频率变化的比例也很高；图形期里，FRS中的比例比MSS中的高出很多。它们对不同运动顺序呈现明显的选择性。对在动物完成FRS和MSS任务的相同运动顺序时放电活动增加的那些神经元所做的比较分析表明，它们在图形期里与FRS的关系要比MSS密切；在MSS的暗示期或图形期里反应潜伏期要比FRS长。以上结果说明背外侧PM区不仅参与MSS行为也参与FRS行为，它可能是功能上不同于PM其它部分的又一个亚区。从细胞反应潜伏期的分析结果推测，参与FRS和MSS行为的神经通路不完全相同，背外侧PM是参与FRS和MSS行为的神经网络中的一个共享结构。

In the last 2~3 decades the role of the premotor cortex (PM) of monkey in memorized spatial sequential (MSS) movements has been amply investigated. However,it is as yet not known whether PM participates in the movement sequence behaviour guided by recognition of visual figures (i. e. the figure-recognition sequence, FRS). In the present work three monkeys were trained to perform both FRS and MSS tasks. Postmortem exdrination showed tha 202 cells were in the dorso-lateral premotor cortex.Amng 111 cells recouled during the two tasks, more than 50% changed their activity during the cue periods in either task. During the response period, the ratios of cells with changes of firing rate in both FRS and MSS were high and mighly equal to each other,while during the image period, the proportion in the FRS (83.7% ) was significantly higher than that in the MSS (66.7% ). Comparison of neuronal activities during same motor sequence of two different tasks showed that during the image periods PM neuronal activities were more closely related to the FRS task, while during the cue periods no difference could be found. Analysis of cell responses showed that the neurons with longer latency were much more in MSS than in FRS in either cue or image period. The present results indicate that the premotor cortex participates in FRS motor sequence as well as in MSS and suggest tha the dorso-lateral PM represents another subarea in function shared by both FRS and MSS tasks. However, in view of the differences of PM neuronal responses in cue or image periods of FRS and MSS tasks, it seems likely that neural networks involved in FRS and MSS tasks are different.