Courjon Jean-Hubert, Olivier Etienne, Pélisson Denis
Espace et Action, Unité 534, INSERM/Université Claude Bernard - Lyon, IFR19 Institut Fédératif des Neurosciences de Lyon, Bron, France.
J Physiol. 2004 May 1;556(Pt 3):675-81. doi: 10.1113/jphysiol.2004.061713. Epub 2004 Mar 12.
The production of visually guided reaching movements relies on a large neural network. Based on indirect experimental evidence, it has been suggested that the superior colliculus, a subcortical centre known for its key role in controlling rapid orienting gaze shifts, also belongs to this network. The aim of the present study was to investigate the role of the cat superior colliculus (SC) in the control of visually guided reaching movements. To address this issue, we studied the effect of SC electrical stimulation on forelimb reaching movements in two cats trained to catch a piece of food. Electrical stimulation delivered just after the movement onset yielded a consistent perturbation of the movement trajectory of the forelimb extremity. This perturbation followed stimulation onset by 56 +/- 11 ms on average, and consisted of a deviation of the spatial path and a deceleration of the movement. The forelimb perturbation was elicited in the absence of concomitant gaze or head displacement in 52% of the stimulation trials. Forelimb perturbations were followed by in-flight adjustments so that reaching movements reliably ended on the target. The present results constitute the first behavioural evidence for a contribution of the cat SC to the control of visually guided forelimb movements.
视觉引导下的伸手动作的产生依赖于一个庞大的神经网络。基于间接实验证据，有人提出上丘（superior colliculus），一个以在控制快速定向眼动转移中起关键作用而闻名的皮层下中枢，也属于这个网络。本研究的目的是调查猫上丘（SC）在视觉引导下的伸手动作控制中的作用。为了解决这个问题，我们研究了在两只经过训练抓取食物的猫中，电刺激上丘对前肢伸手动作的影响。在动作开始后立即施加电刺激会导致前肢末端运动轨迹的持续扰动。这种扰动平均在刺激开始后56±11毫秒出现，包括空间路径的偏差和运动的减速。在52%的刺激试验中，前肢扰动是在没有伴随的注视或头部位移的情况下引发的。前肢扰动之后会有飞行中的调整，以便伸手动作可靠地在目标上结束。目前的结果构成了猫上丘对视觉引导下的前肢运动控制有贡献的首个行为证据。
