Visuomotor functions of central thalamus in monkey. II. Unit activity related to visual events, targeting, and fixation.
Visuomotor functions of central thalamus in monkey. II. Unit activity related to visual events, targeting, and fixation.
复制标题
猴中央丘脑的视觉运动功能。
DOI：
10.1152/jn.1984.51.6.1175
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发表时间：
1984
影响因子：
2.5
通讯作者：
Schlag-Rey,M
中科院分区：
文献类型：
--
作者：
Schlag,J;Schlag-Rey,M
在警觉的猴子中，在观察到眼球运动相关活动的丘脑中央区域记录了对视觉刺激的单一单元反应（33）。通常，刺激是在切线屏幕上出现在不可预测位置的1度环状暗淡光。动物们接受了两项任务的训练：一项任务是，它们自己按下一个面板来传递刺激，当刺激的形状变成方形时，它们必须立即释放这个面板；另一项任务是，实验者打开刺激，猴子们在预定的时间内盯着这个目标，就会得到奖励。在这两项任务中，都需要持续的刺激固定。接受野在有注视点和没有注视点的情况下进行了测试。通过从空间刺激坐标中减去眼睛位置坐标，获得刺激的视网膜坐标，猴子的头部是固定的。在发生靶向或未发生靶向的情况下，分别分析单位反应。63个单位观察到短暂反应，44个单位观察到持续反应。在63个反应短暂的单位中，有42个单位不考虑目标。他们的感受野非常大，通常包括中央凹，当感受野不对称时主要是对侧的。其他21个单位的反应取决于目标的发生。他们被称为视觉触发眼动相关反应（VTEM）。VTEM单元进一步细分为9个仅具有靶向活性的单元和12个在这种情况下表现出经典的“反应增强”现象的单元。VTEM单元与6个单元形成对比，这6个单元都是被动的视觉反应，并伴有自发或视觉触发的扫视。在80%的单元中，被动视觉和VTEM对刺激的反应潜伏期在77 ~ 135 ms之间。VTEM单位也在重新瞄准扫视前开火。自发眼跳活跃的前额叶单元也与视觉诱发的眼跳一起放电。刺激开始后引发扫视的最早激活迹象出现在80 ~ 100 ms之间，即与被动视觉和VTEM单元处于相同的潜伏期范围。持续的视觉反应包括18个单元的激活和26个单元的失活。这些放电模式的发生与刺激固定有关。在大多数情况下，放电频率的变化开始于固定之前，通过目标扫视实现。它们在注视被远离刺激的扫视打破之前就终止了。（摘要删节为400字）
In alert monkeys, single-unit responses to visual stimuli were recorded in the central thalamic region where eye movement-related activity has been observed (33). Usually, the stimuli were 1 degree annulus patterns of dim light presented at unpredictable locations on a tangent screen. The animals were trained on two tasks: one in which they delivered the stimulus themselves by pressing a panel that they had to release immediately when the stimulus shape changed to a square, and another one in which the stimulus was turned on by the experimenter and the monkeys were rewarded for fixating this target for a predetermined length of time. In both tasks, continuous stimulus fixation was required. Receptive fields were tested with and without a fixation point. Retinal coordinates of stimuli were obtained by subtracting eye-position coordinates from stimulus coordinates in space, the monkey's head being fixed. Unit responses in the cases where targeting occurred or did not occur were analyzed separately. Transient responses were observed in 63 units and sustained responses in 44 units. Among the 63 units responding transiently, 42 did so irrespective of targeting. Their receptive fields were very large, generally including the fovea, and predominantly contralateral when the fields were asymmetric. The responses of the other 21 units depended on the occurrence of targeting. They were called visually triggered eye movement-related responses (VTEM). VTEM units were further subdivided in 9 units active only with targeting and 12 units showing the classical phenomenon of "response enhancement" under this condition. VTEM units were contrasted to six units that were both passively visually responsive and bursting with saccades, either spontaneous or visually triggered. The latencies of passive visual and VTEM responses to stimulus onset were comprised between 77 and 135 ms in 80% of the units. VTEM units also fired prior to retargeting saccades. Presaccadic units active with spontaneous saccades also discharged with visually elicited saccades. The earliest sign of activation after stimulus onset eliciting a saccade appeared between 80 and 100 ms, that is, in the same range of latencies as passive visual and VTEM units. Sustained visual responses consisted of activation in 18 units and inactivation in 26 units. The occurrence of these patterns of firing was related to stimulus fixation. In the majority of cases, the changes in discharge frequency started before fixation was achieved by a targeting saccade. They terminated before fixation was broken by a saccade away from the stimulus.(ABSTRACT TRUNCATED AT 400 WORDS)