Superior Colliculus inactivation causes stable offsets in eye position during tracking
Superior Colliculus inactivation causes stable offsets in eye position during tracking
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DOI：
10.1523/jneurosci.1317-08.2008
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发表时间：
2008-08-06
影响因子：
5.3
通讯作者：
Krauzlis, Richard J.
中科院分区：
文献类型：
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作者：
Hafed, Ziad M.;Goffart, Laurent;Krauzlis, Richard J.
灵长类上丘(SC)通常被认为由两个功能互补的不同运动区组成：一个是帮助产生对偏心目标的眼跳的外围区域，另一个是通过抑制眼跳来维持注视的中央区域。在这里，我们直接测试了另一种解释，即SC的地形不是严格意义上的运动，也不是形成两个不同的区域，而是形成行为相关目标位置的单一地图。灵长类动物跟踪两个运动刺激之间看不见的中点，因此引导跟踪的刺激是外围的，而推断的运动目标是中心凹和旁中央凹。SC地形图中央部分神经元的暂时失活代表了看不见的目标，在跟踪过程中导致眼睛位置的稳定偏移，这些偏移量被定向远离由失活的SC位置编码的视网膜位置。关键的是，这些补偿并没有伴随着系统性地无法产生或抑制眼跳，它们也不能完全用眼跳、顺畅追赶或注视中的运动缺陷来解释。此外，偏移量的大小取决于失活部位的偏心率以及与行为目标相关的空间不确定性程度。这些结果表明，凝视控制依赖于SC中目标位置地图上的活动平衡，通过沉默代表行为目标的正常活动群体中的一些神经元，焦点失活导致对看向哪里的偏见估计。
The primate superior colliculus ( SC) is often viewed as composed of two distinct motor zones with complementary functions: a peripheral region that helps generate saccades to eccentric targets and a central one that maintains fixation by suppressing saccades. Here, we directly tested the alternative interpretation that topography in the SC is not strictly motor, nor does it form two distinct zones, but instead forms a single map of behaviorally relevant goal locations. Primates tracked the invisible midpoint between two moving stimuli, such that the stimuli guiding tracking were peripheral whereas the inferred movement goal was foveal and parafoveal. Temporary inactivation of neurons in the central portion of the topographicmapof the SC, representing the invisible goal, caused stable offsets in eye position during tracking that were directed away from the retinotopic position encoded by the inactivated SC site. Critically, these offsets were not accompanied by a systematic inability to generate or suppress saccades, and they were not fully explained by motor deficits in saccades, smooth pursuit, or fixation. In addition, the magnitude of the offset depended on the eccentricity of the inactivated site as well as the degree of spatial uncertainty associated with the behavioral goal. These results indicate that gaze control depends on the balance of activity across a map of goal locations in the SC, and that by silencing some of the neurons in the normally active population representing the behavioral goal, focal inactivation causes a biased estimate of where to look.