Role of frontal eye fields in countermanding saccades: Visual, movement, and fixation activity
Role of frontal eye fields in countermanding saccades: Visual, movement, and fixation activity
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DOI：
10.1152/jn.1998.79.2.817
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发表时间：
1998-02-01
影响因子：
2.5
通讯作者：
Schall, JD
中科院分区：
文献类型：
--
作者：
Hanes, DP;Patterson, WF;Schall, JD
开发了一种新的方法来研究视觉、运动和注视相关的神经活动在凝视控制中的作用。我们记录了猕猴(Macaca Mulatta)在视觉和记忆引导的眼跳中的额眼区域(FEF)的单位活动，FEF是额叶皮质中的一个区域，在产生有目的的眼动方面发挥着核心作用。使用反向范式来评估单个细胞是否能够产生足以控制运动产生的信号。对抗模式包括一项任务，该任务操纵猴子扣留计划的扫视的能力，以及一项基于竞赛模型的分析，该模型提供了取消正在准备的运动所需时间的估计。我们获得了明确的证据，表明具有眼动相关活动的FEF神经元产生的信号足以控制凝视转移的产生。随着眼跳的准备，与运动相关的活动逐渐增长到触发阈值，但在取消眼跳所需的时间内，随着停止信号的响应，运动相关活动逐渐衰退。具有凝视相关活动的神经元不太常见，但在反拨范式中，这些神经元表现出同样清晰的凝视控制信号。在眼跳被取消的时间内，在眼跳前暂停放电的固定细胞表现出对停止信号的反应增加的活动。与具有运动或固定活动的细胞相比，只有视觉诱发活动的神经元没有证据表明信号足以控制凝视转移的产生。然而，一旦眼跳指令被取消，一小部分紧张性视觉细胞表现出活动减少，即使视觉目标仍然存在于接受野中。这些发现证明了反拨范式在识别运动控制的神经特征方面的使用，并提供了关于凝视转移和凝视保持机制之间微妙平衡的新信息。
A new approach was developed to investigate the role of visual-, movement-, and fixation-related neural activity in gaze control. We recorded unit activity in the frontal eye fields (FEF), an area in frontal cortex that plays a central role in the production of purposeful eye movements, of monkeys (Macaca mulatta) performing visually and memory-guided saccades. The countermanding paradigm was employed to assess whether single cell; generate signals sufficient to control movement production. The countermanding paradigm consists of a task that manipulates the monkeys' ability to withhold planned saccades combined with an analysis based on a race model that provides an estimate of the time needed to cancel the movement that is being prepared. We obtained clear evidence that FEF neurons with eye movement related activity generate signals sufficient to control the production of gaze shifts. Movement-related activity, which was growing toward a trigger threshold as the saccades were prepared, decayed in response to the stop signal within the time required to cancel the saccade. Neurons with fixation-related activity were less common, but during the countermanding paradigm, these neurons exhibited an equally clear gaze-control signal. Fixation cells that had a pause in firing before a saccade exhibited elevated activity in response to the stop signal within the time that the saccade was cancelled. In contrast to cells with movement or fixation activity, neurons with only visually evoked activity exhibited no evidence of signals sufficient to control the production of gaze shifts. However, a fraction of tonic visual cells exhibited a reduction of activity once a saccade command had been cancelled even though the visual target was still present in the receptive field. These findings demonstrate the use of the countermanding paradigm in identifying neural signatures of motor control and provide new information about the fine balance between gaze shifting and gaze holding mechanisms.