Activity of cells in the deeper layers of the superior colliculus of the rhesus monkey: Evidence for a gaze displacement command
Activity of cells in the deeper layers of the superior colliculus of the rhesus monkey: Evidence for a gaze displacement command
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DOI：
10.1152/jn.1997.78.3.1669
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发表时间：
1997-09-01
影响因子：
2.5
通讯作者：
Sparks, DL
中科院分区：
文献类型：
--
作者：
Freedman, EG;Sparks, DL
当头部自由移动时，灵长类上丘（SC）的微刺激会引起眼睛和头部的协调运动。这些刺激引起的运动和视觉引导运动之间的相似性表明，灵长类动物的 SC 参与了视线（凝视）的重定向。为了确定单个丘脑神经元如何表示运动命令，我们记录了恒河猴上丘深层单细胞在协调眼头注视转移期间的活动。测试了两个替代假设。 “单独通道”假设指出，SC 生成两个位移命令：一个信号指定眼球运动的幅度和方向，第二个信号指定头部运动的幅度和方向。或者，SC 可以生成单个凝视位移命令（“凝视位移”假设）。在凝视、眼睛和头部运动幅度和方向（度量）的三种行为分离过程中检查了丘脑神经元的活动。选择的试验子集中，目光移动或眼球运动或头部运动的幅度和方向相对恒定，但其他两项的指标变化范围很大。在这些条件下，单独的通道和注视位移假设对 SC 活动模式做出不同的预测。我们通过将观察到的模式与神经元活动的预测模式进行比较来测试这些差异预测。我们获得的数据与注视位移假设的预测一致。单独通道假说的预测并未得到证实。因此，微刺激数据、单单元记录数据和行为数据都与丘功能的凝视位移假设一致——该假设认为凝视位移信号源自SC运动图内的活动轨迹，随后被分解为丘下游的单独的眼睛和头部位移信号。
When the head is free to move, microstimulation of the primate superior colliculus (SC) evokes coordinated movements of the eyes and head. The similarity between these stimulation-induced movements and visually guided movements indicates that the SC of the primate is involved in redirecting the line of sight (gaze). To determine how movement commands are represented by individual collicular neurons, we recorded the activity of single cells in the deeper layers of the superior colliculus of the rhesus monkey during coordinated eye-head gaze shifts. Two alternative hypotheses were tested. The ''separate channel'' hypothesis states that two displacement commands are generated by the SC: one signal specifying the amplitude and direction of eye movements and a second signal specifying the amplitude and direction of head movements. Alternatively, a single gaze displacement command could be generated by the SC (''gaze displacement'' hypothesis). The activity of collicular neurons was examined during three behavioral dissociations of gaze, eye, and head movement amplitude and direction (metrics). Subsets of trials were selected in which the amplitude and direction of either gaze shifts or eye movements or head movements were relatively constant but the metrics of the other two varied over wide ranges. Under these conditions, the separate channel and gaze displacement hypotheses make differential predictions about the patterns of SC activity. We tested these differential predictions by comparing observed patterns with predicted patterns of neuronal activity. We obtained data consistent with the predictions of the gaze displacement hypothesis. The predictions of the separate channel hypothesis were not confirmed. Thus microstimulation data, single-unit recording data, and behavioral data are all consistent with the gaze displacement hy pothesis of collicular function-the hypothesis that a gaze displacement signal is derived from the locus of activity within the motor map of the SC and subsequently is decomposed into separate eye and head displacement signals downstream from the colliculus.