Supplementary eye field: representation of saccades and relationship between neural response fields and elicited eye movements.
Supplementary eye field: representation of saccades and relationship between neural response fields and elicited eye movements.
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DOI：
10.1152/jn.2000.84.5.2605
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发表时间：
2000-11
影响因子：
2.5
通讯作者：
Gary S. Russo;Charles J. Bruce
中科院分区：
文献类型：
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作者：
Gary S. Russo;Charles J. Bruce
通过分析眼跳前活动、电刺激眼跳以及它们之间的关系，研究了低阈值补充眼场的功能组织。响应场最佳向量，定义为视野坐标或扫视眼动尺寸唤起最高的神经放电，定量估计160 SEF神经元系统地改变周边目标位置相对于中央固定点，然后拟合高斯函数的响应。在中央注视期间，通过微刺激（70 ms，10-100 microA）在109个SEF部位电诱发扫视。反应场和诱发眼跳的分布表明，SEF中所有对侧眼跳的完整代表性。引发的扫视极方向范围在97和262度之间（从左半球的数据被转换为右半球的约定），幅度范围在1.8和26.9度之间。反应场最佳向量（右半球转换）几乎都是对侧的，以及115/119视觉反应场和80/84运动反应场的方向范围在90和279度之间，反应场的偏心率范围在5和50度之间。视觉运动神经元的视觉和运动活动的反应场方向呈强相关（r = 0.95）。当神经活动和引发的眼跳在完全相同的网站进行了比较，响应字段高度预测引发的眼跳尺寸。反应场方向与记录部位的扫视方向高度相关（r = 0.92，n = 77）。同样，响应场偏心预测随后的电引起的扫视的大小（r = 0.49，n = 60）。然而，引起的扫视一般小于响应场偏心率和一贯更水平的响应场几乎垂直时。极方向的反应领域和引发扫视保持恒定的垂直于皮质表面，表示一个柱状组织扫视方向。扫视方向逐步转移整个SEF，然而，这些有序的转变更表明一个超柱状组织，而不是一个单一的全球地形。眼跳幅度没有明显的系统性组织。我们的结论是，扫视表示在SEF一致的视觉感受野，前运动场，和传出映射。因此，SEF指定眼跳向量作为局部神经元组的活动的突发，其具有向下游眼神经结构的适当投射。在这方面，SEF的组织像上级丘和额眼场，即使SEF缺乏一个整体的全球扫视地形。我们认为，SEF的所有专门眼科功能都必须在这个基本组织的范围内运作。
The functional organization of the low-threshold supplementary eye field (SEF) was studied by analyzing presaccadic activity, electrically elicited saccades, and the relationship between them. Response-field optimal vectors, defined as the visual field coordinates or saccadic eye-movement dimensions evoking the highest neural discharge, were quantitatively estimated for 160 SEF neurons by systematically varying peripheral target location relative to a central fixation point and then fitting the responses to Gaussian functions. Saccades were electrically elicited at 109 SEF sites by microstimulation (70 ms, 10-100 microA) during central fixation. The distribution of response fields and elicited saccades indicated a complete representation of all contralateral saccades in SEF. Elicited saccade polar directions ranged between 97 and 262 degrees (data from left hemispheres were transformed to a right-hemisphere convention), and amplitudes ranged between 1.8 and 26.9 degrees. Response-field optimal vectors (right hemisphere transformed) were nearly all contralateral as well; the directions of 115/119 visual response fields and 80/84 movement response fields ranged between 90 and 279 degrees, and response-field eccentricities ranged between 5 and 50 degrees. Response-field directions for the visual and movement activity of visuomovement neurons were strongly correlated (r = 0.95). When neural activity and elicited saccades obtained at exactly the same sites were compared, response fields were highly predictive of elicited saccade dimensions. Response-field direction was highly correlated with the direction of saccades elicited at the recording site (r = 0.92, n = 77). Similarly, response-field eccentricity predicted the size of subsequent electrically elicited saccades (r = 0.49, n = 60). However, elicited saccades were generally smaller than response-field eccentricities and consistently more horizontal when response fields were nearly vertical. The polar direction of response fields and elicited saccades remained constant perpendicular to the cortical surface, indicating a columnar organization of saccade direction. Saccade direction progressively shifted across SEF; however, these orderly shifts were more indicative of a hypercolumnar organization rather than a single global topography. No systematic organization for saccade amplitude was evident. We conclude that saccades are represented in SEF by congruent visual receptive fields, presaccadic movement fields, and efferent mappings. Thus SEF specifies saccade vectors as bursts of activity by local groups of neurons with appropriate projections to downstream oculomotor structures. In this respect, SEF is organized like the superior colliculus and the frontal eye field even though SEF lacks an overall global saccade topography. We contend that all specialized oculomotor functions of SEF must operate within the context of this fundamental organization.