Fixation and saccade generation by the frontal eye field

众所周知，额眼场（FEF）负责扫视眼动的产生。最近，事实证明，FEF也参与产生平滑的追求眼球运动和会聚眼球movement.In相比之下，本研究的目的是确定在FEF的电刺激产生的扫视眼球运动的抑制在猴子的区域。此外，通过改变电刺激的各种参数，研究了眼跳抑制的特性。为了达到这个目的，这些猴子被以传统的方式训练，对它们面前屏幕上的视觉目标进行视觉引导的扫视。然后，系统地调查FEF，以找到刺激抑制视觉引导扫视的区域。皮质内微刺激的刺激强度被限制为小于50 μA。在刺激产生扫视的经典FEF的一个相当宽的区域中， ...更多信息 而100 μA、50 μA以下的刺激均能抑制同侧和对侧的眼跳。刺激该部位可抑制8个方向的眼跳，且抑制强度基本相等。这种抑制随着刺激持续时间的增加而持续。对同侧和对侧眼跳抑制的持续时间低至10 μA，几乎相等。为了检查FEF的该抑制区域中的神经元的性质，在固定任务期间记录尖峰。即使没有注视目标，该区域的神经元在注视过程中也表现出活动的增加。这些神经元在任何方向的扫视开始时都停止了放电。这些神经元对固定任务的响应的进一步特性现在正在研究中。少

It has been well known that the frontal eye field (FEF) is responsible for generation of saccadic eye movements. Recently, it turns out that the FEF is also involved in generating smooth pursuit eye movement and convergence eye movement.In contrast, the present study was aimed at identifying the area in the FEF where electrical stimulation produced suppression of saccadic eye movements in the monkey. In addition, the properties of the suppression on saccades were investigated by changing various parameters for the electrical stimulation. For this purpose, the monkeys were trained in a conventional way to make visually-guided saccades to a visual target on the screen in front of them. Then, the FEF was systematically surveyed to find an area whose stimulation suppresses visually-guided saccades. Stimulus intensity for intracortical microstimulation was limited to less than 50 μA. In a fairly wide area of the classical FEF where stimulation produced saccades, stimulation with intensities … More sub threshold for saccade generation could suppress the saccades ipsilateral to the stimulation side, but not the saccades contralateral to it. In contrast, stimulation of the area adjacent to the classical FEF where no saccades were evoked at 100 μA, stimulation at less than 50 μA could easily suppress saccades in both ipsi- and contralateral directions. Stimulation of this site suppressed saccades in 8 directions covering all directions, and strengths of the suppression on the saccades in these different directions were almost equal. This suppression continued as the stimulus duration was increased. Thresholds for the suppression on saccades in ipsi- and contralateral directions were as low as 10 μA and almost equal. To examine the properties of neurons in this suppression area of the FEF, spikes were recorded during the fixation task. Neurons in this area showed increase of activities during the fixation even without a fixation target. These neurons stopped firing at the onset of saccades in any directions. Further properties of these neurons in response to the fixation task are now being investigated. Less