Godschalk M, Lemon R N, Kuypers H G, van der Steen J
Behav Brain Res. 1985 Nov-Dec;18(2):143-57. doi: 10.1016/0166-4328(85)90070-1.
Some neurones in macaque postarcuate premotor area modulate their firing frequency in relation to motor tasks which require visual information. We previously reported that a large proportion of these neurones modulate during execution of a detour reaching task in which the movement phase was separated in time from the phase in which the monkey received a visual cue for the movement required to retrieve a food reward. A large proportion of task-related neurones (75%) modulated during this 'visual' phase, in which no task-related movements were made. This modulation was related to the position of the food reward, which served as the visual cue. Most of these neurones were located in cortical area 6, close to the arcuate curvature and its spur, but also more caudally in area 4 and rostrally in area 8. In the present chronic recording experiments in monkeys, several variations of the original task were used in order to test whether the 'visual'-related neuronal modulation could be involved in preparation of the upcoming movement. This modulation is unlikely to be related to any eye or arm movements occurring during the visual phase or to changes in environmental illumination. Neither can it be related to the presence of the visual cue in a particular part of the visual field, since the pattern of neuronal modulation was similar when a cue with a fixed position was used. This modulation was, however, contingent upon the occurrence of food retrieval during the subsequent 'movement phase', since it was abolished or diminished during presentation of a 'food-reward' which the monkey did not retrieve. For several neurones, modulation pattern during the visual phase depended on whether the food reward was to be retrieved with a gross hand movement or with relatively independent finger movements. It is likely, therefore, that neurones in the postarcuate premotor cortex are involved in preparation for arm movements with the help of visual cues. The results are discussed in view of corticocortical pathways which might be involved in transmission of visual information from visual areas through parietal association areas and premotor cortex to the primary motor cortex.
猕猴弓状后运动前区的一些神经元会根据需要视觉信息的运动任务来调节其放电频率。我们之前报道过，在执行迂回伸手任务时，这些神经元中有很大一部分会发生调节，在该任务中，运动阶段与猴子接收用于获取食物奖励所需运动的视觉提示的阶段在时间上是分开的。在这个“视觉”阶段，大部分与任务相关的神经元（75%）发生了调节，而在此阶段没有进行与任务相关的运动。这种调节与作为视觉提示的食物奖励的位置有关。这些神经元中的大多数位于皮质6区，靠近弓状弯曲及其分支，但在4区更靠尾侧，在8区更靠前。在目前对猴子进行的慢性记录实验中，使用了原始任务的几种变体，以测试与“视觉”相关的神经元调节是否可能参与即将到来的运动的准备。这种调节不太可能与视觉阶段发生的任何眼部或手臂运动或环境光照的变化有关。它也不可能与视觉场特定部分中视觉提示的存在有关，因为当使用固定位置的提示时，神经元调节模式是相似的。然而，这种调节取决于后续“运动阶段”中食物获取的发生情况，因为在猴子未获取的“食物奖励”呈现期间，它会被消除或减弱。对于一些神经元，视觉阶段的调节模式取决于食物奖励是要用粗大的手部运动还是相对独立的手指运动来获取。因此，弓状后运动前皮质中的神经元很可能在视觉提示的帮助下参与手臂运动的准备。我们根据可能参与视觉信息从视觉区域通过顶叶联合区域和运动前皮质传输到初级运动皮质的皮质皮质通路来讨论这些结果。
