PRIMATE FRONTAL EYE FIELDS .1. SINGLE NEURONS DISCHARGING BEFORE SACCADES
PRIMATE FRONTAL EYE FIELDS .1. SINGLE NEURONS DISCHARGING BEFORE SACCADES
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DOI：
10.1152/jn.1985.53.3.603
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发表时间：
1985-01-01
影响因子：
2.5
通讯作者：
GOLDBERG, ME
中科院分区：
文献类型：
--
作者：
BRUCE, CJ;GOLDBERG, ME
研究了被训练完成几种视觉任务的清醒猕猴的额叶眼野中单个神经元的活动。54%的神经元在视觉引导的扫视之前放电。三种不同类型的preschadic活动进行了观察：视觉，运动和预期。无论猴子是否进行扫视，视觉活动都是对视觉刺激的反应。运动活动之前有目的的扫视，即使是那些没有视觉目标。如果猴子能够可靠地预测他必须做什么样的扫视，那么预期活动甚至先于做出扫视的暗示。这3种活性在不同部位的不同前囊细胞中存在差异。20%的前扫视神经元在没有视觉目标的情况下进行有目的的扫视之前放电活跃，就像在视觉引导的扫视之前一样，并且视觉反应很弱或不存在。这些细胞被定义为运动细胞。在没有任务要求或明显的视觉目标的自发扫视之前，运动细胞放电少得多或根本不放电。其余的前视神经元（40%）具有视觉和运动活动（视觉运动细胞）。在视觉引导的眼球运动之前，他们最活跃地放电，但在黑暗中有目的的眼球运动之前也放电，并且在没有扫视的情况下对视觉刺激做出反应。从视觉活动占主导地位的细胞到运动活动占主导地位的细胞，视觉运动细胞是一个连续体。这种连续性表明，虽然视觉细胞与运动细胞截然不同，但将细胞类型分为3类可能只是描述从视觉输入到眼动输出的处理流程的启发式方法。20%的视觉运动和运动细胞，但不到2%的视觉细胞，有预期的活动。只有1个细胞具有作为其唯一反应的预期活性。当眼跳相对于目标起始延迟时，视觉细胞对目标出现作出反应，运动细胞在眼跳之前放电，视觉运动细胞在延迟期间以不同的方式放电，通常在眼跳之前有一些放电和速率增加。所有类型的前扫视神经元积极抑制后扫视到他们的反应领域。所有的preschaccadic活动是选择性的刺激尺寸。运动和视觉运动细胞放电绘制为扫视方向和幅度的函数。方向图拟合高斯函数，振幅图拟合对数高斯函数。与视觉细胞相比，运动细胞对方向和幅度的调节不那么敏锐。视觉运动细胞具有中间调谐。额叶眼区的神经元活动表明，该区域在产生随意扫视眼球运动中具有重要作用。
The activity of single neurons in the frontal eye fields of awake macaque monkeys trained to perform several oculomotor tasks was studied. Fifty-four precent of neurons discharged before visually guided saccades. Three different types of presacchadic activity were observed: visual, movement and anticipatory. Visual activity occurred in response to visual stimuli whether or not the monkey made saccades. Movement activity preceded purposive saccades, even those made without visual targets. Anticipatory activity preceded even the cue to make a saccade if the monkey could reliably predict what saccade he had to make. These 3 different activities were found in different presaccadic cells in different porportions. Twenty percent of presaccadic neurons discharged as briskly before purposive saccades made without a visual target as they did before visually guided saccades and had weak or absent visual responses. These cells were defined as movement cells. Movement cells discharged much less or not at all before saccades made spontaneously without a task requirement or an overt visual target. The remaining presaccadic neurons (40%) had both visual and movement activity (visuomovement cells). They discharged most briskly before visually guided eye movements, but also discharged before purposive eye movements made in darkness and responded to visual stimuli in the absence of saccades. There was a continuum of visuomovement cells, from cells in which visual activity predominated to cells in which movement activity predominated. This continuum suggests that although visual cells are quite distinct from movement cells, the division of cell types into 3 classes may be only a heuristic means of describing the processing flow from visual input to eye-movement output. Twenty percent of visuomovement and movement cells, but fewer than 2% of visual cells, had anticipatory activity. Only 1 cell had anticipatory activity as its sole response. When the saccade was delayed relative to the target onset, visual cells responded to the target appearance, movement cells discharged before the saccade and visuomovement cells discharged in different ways during the delay, usually with some discharge following the target and an increase in rate immediately before the saccade. Presaccadic neurons of all types were actively suppressed following a saccade into their response fields. All presaccadic activity was selective for stimulus dimensions. Movement- and visuomovement-cell discharge was plotted as a function of saccade direction and amplitude. Direction plots were fit to a Gaussian function and amplitude plots fit to a log-Gaussian function. Movement cells were less sharply tuned to direction and amplitude than were visual cells. Visuomovement cells had intermediate tuning. The neuronal activity in the frontal eye fields indicates that this area has an important role in generating voluntary saccadic eye movements.