Yin T C, Greenwood M
Department of Neurophysiology, University of Wisconsin, Madison 53706.
Exp Brain Res. 1992;88(1):15-32. doi: 10.1007/BF02259125.
We studied visuomotor processing in the middle (MS) and lateral suprasylvian (LS) cortices of the alert cat by making single cell recordings while the cat was working in a behavioral task requiring visual fixation and visually guided eye movements. We found responses with three different components: visual sensory, saccade-related motor, and fixation. Some cells exhibited purely visual responses and all of their activity during visuomotor tasks could be attributed to the sensory aspects of the task. Other cells showed no sensory response properties, but discharged in relation to the saccadic eye movements that the cat made to visual targets. A smaller number of fixation cells displayed increased discharge when the cat fixated a target light and usually only when that target was in a particular region of the visual field. These response components could be present in a variety of combinations in different cells, of which the largest proportion combined visuomotor responses and could take five general forms: simple visuomotor, saccadic enhanced, visually triggered movement (VTM), enhanced VTM, and disenhanced. Simple visuomotor responses had both a visual and saccade-related component. Saccadic enhanced responses had a visual response to the appearance of a spot in the cell's receptive field that became enhanced when the cat subsequently made a saccade to that spot. The VTM responses were synchronized better to the visual stimulus than to the saccade, but they also exhibited properties expected of motor responses. The last two classes of visuomotor responses were rare: one we termed enhanced VTM and the other disenhanced. Cells could combine different visuomotor response components or even sensory, saccade-related and fixation responses in different combinations for different directions of eye movements. Generally, the timing of the saccade-related responses occurred too late to play a role in the initiation of saccades: most (83%) saccade-related responses occurred between 40 ms before to 80 ms after the onset of the eye movement. Cells of all different types could be found in both the MS and LS areas, though in general the responses in LS were more sensory in nature while those in MS were more closely related to the eye movement. About a quarter of the cells were unresponsive during any aspect of our tasks.
我们通过在警觉的猫执行需要视觉注视和视觉引导眼球运动的行为任务时进行单细胞记录，研究了猫脑中间（MS）和外侧上薛氏回（LS）皮质中的视觉运动处理。我们发现了具有三种不同成分的反应：视觉感觉、与扫视相关的运动和注视。一些细胞表现出纯粹的视觉反应，并且它们在视觉运动任务期间的所有活动都可归因于任务的感觉方面。其他细胞没有感觉反应特性，但与猫对视觉目标进行的眼球扫视运动相关放电。当猫注视目标光时，少数注视细胞放电增加，并且通常仅当该目标位于视野的特定区域时才会如此。这些反应成分可以以各种组合形式存在于不同的细胞中，其中最大比例的组合是视觉运动反应，并且可以采取五种一般形式：简单视觉运动、扫视增强、视觉触发运动（VTM）、增强型VTM和减弱型。简单视觉运动反应既有视觉成分又有与扫视相关的成分。扫视增强反应对细胞感受野中出现的一个点有视觉反应，当猫随后向该点进行扫视时，这种反应会增强。VTM反应与视觉刺激的同步性比对扫视的同步性更好，但它们也表现出运动反应所预期的特性。最后两类视觉运动反应很少见：一类我们称为增强型VTM，另一类为减弱型。细胞可以针对不同方向的眼球运动以不同组合方式组合不同的视觉运动反应成分，甚至是感觉、与扫视相关和注视反应。一般来说，与扫视相关的反应发生时间太晚，无法在扫视启动中发挥作用：大多数（83%）与扫视相关的反应发生在眼球运动开始前40毫秒至开始后80毫秒之间。在MS和LS区域都可以找到所有不同类型的细胞，不过一般来说，LS区域的反应在本质上更具感觉性，而MS区域的反应与眼球运动的关系更密切。在我们任务的任何方面，约四分之一的细胞没有反应。
