Target selection for saccadic eye movements: Prelude activity in the superior colliculus during a direction-discrimination task
Target selection for saccadic eye movements: Prelude activity in the superior colliculus during a direction-discrimination task
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DOI：
10.1152/jn.2001.86.5.2543
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发表时间：
2001-11-01
影响因子：
2.5
通讯作者：
Newsome, WT
中科院分区：
文献类型：
--
作者：
Horwitz, GD;Newsome, WT
我们研究了猕猴进行方向辨别任务时，上级丘（SC）在扫视目标选择中的作用。猴子选择两个可能的眼跳目标之一的基础上的运动方向在一个随机的随机点显示;任务的难度是不同的，通过调整显示器中的运动信号的强度。两个扫视目标之一被定位在所研究的SC神经元的运动场内，而另一个目标被定位在运动场外。大约30%的神经元在中间和深层的SC放电的活动，“预测”目标的选择以及执行扫视眼球运动之前的目标特定的前奏。在整个神经元群体中，显示器中运动信号的强度影响了这种“预测性”前奏活动的强度：当运动信号强时，SC活动比弱时更可靠地发出即将到来的扫视信号。神经活动对运动强度的依赖性不能用扫视眼球运动度量的微小变化来解释。在我们之前描述过的具有方向性视觉反应的神经元亚群中，预测活性特别强。因此，对于SC神经元的一个子集，前奏活动反映了除了即将到来的眼跳的目标之外的方向辨别的难度。这些结果与SC神经元的受限网络在扫视目标选择过程中起作用的概念是一致的。
We investigated the role of the superior colliculus (SC) in saccade target selection while macaque monkeys performed a direction-discrimination task. The monkeys selected one of two possible saccade targets based on the direction of motion in a stochastic random-dot display; the difficulty of the task was varied by adjusting the strength of the motion signal in the display. One of the two saccade targets was positioned within the movement field of the SC neuron under study while the other target was positioned well outside the movement field. Approximately 30% of the neurons in the intermediate and deep layers of the SC discharged target-specific preludes of activity that "predicted" target choices well before execution of the saccadic eye movement. Across the population of neurons, the strength of the motion signal in the display influenced the intensity of this "predictive" prelude activity: SC activity signaled the impending saccade more reliably when the motion signal was strong than when it was weak. The dependence of neural activity on motion strength could not be explained by small variations in the metrics of the saccadic eye movements. Predictive activity was particularly strong in a subpopulation of neurons with directional visual responses that we have described previously. For a subset of SC neurons, therefore, prelude activity reflects the difficulty of the direction discrimination in addition to the target of the impending saccade. These results are consistent with the notion that a restricted network of SC neurons plays a role in the process of saccade target selection.