Integrative approach for the cortical control of eye and hand movements

初级视觉皮层损伤后，视觉引导下的眼球跳跃性运动在1-2个月内恢复到受损视野内呈现的目标。恢复后，视觉信号主要由上丘处理。在特定情况下，从视网膜到SC浅层的直接视觉输入可以直接激活SC中间层的神经元，然后进一步激活脑干下游的眼跳产生电路，触发超短潜伏期的眼跳，称为快速眼跳。在初级运动皮层与手部运动神经元的直接皮质-运动神经元连接受损后，猴子灵巧的手指运动一度受损，但经过1-2个月的训练即可恢复。这种恢复是由位于运动神经元吻侧的几段本体脊髓神经元介导的皮质-运动神经元间接通路促成的。

After the lesion of the primary visual cortex, visually guided saccadic eye movements towards the targets presented in the affected visual field recovers within 1-2 months in monkeys. After the recovery, the visual signal is processed mainly by the superior colliculus (SC). Under particular circumstances, the direct visual inputs from the retina to the superficial layer of the SC can directly activate the neurons in the intermediate layer of the SC and then the further activation of the saccade generator circuits downstream in the brainstem triggers ultra-short latency saccades named express saccades.After the lesion of the direct cortico-motoneuronal connections from the primary motor cortex to hand motoneurons, dexterous finger movements are once impaired but recover through training within 1-2 months in monkeys. Such recovery is contributed by the indirect cortico-motoneuronal pathway mediated by propriospinal neurons located a few segments rostral to motoneurons.