Context dependency in the globus pallidus internal segment during targeted arm movements
Context dependency in the globus pallidus internal segment during targeted arm movements
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DOI：
10.1152/jn.2001.85.2.998
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发表时间：
2001-02-01
影响因子：
2.5
通讯作者：
Houk, JC
中科院分区：
文献类型：
--
作者：
Gdowski, MJ;Miller, LE;Houk, JC
记录和分析了视觉引导前臂旋转到四个不同靶点时苍白球内段单个神经元的细胞外放电。我们试图研究GPI神经元如何对运动准备和执行做出贡献。在35个电极穿透中记录的108个GPI神经元的单位放电与各种行为事件的时间一致，包括线索运动和返回运动的开始。总体而言，108个GPI神经元中有39个(36%)是任务调制的，在视觉线索呈现和运动产生之间的不同时间显示出显著的放电率变化。尽管少数神经元(n=5)在提示(n=32)和返回(n=2)这两个运动阶段都得到了很好的调制，但大多数情况下，在任务的线索(n=32)或返回(n=2)阶段都选择性地发生了对放电频率的强烈调制。在34个在线索运动或返回运动中被完全调制的神经元中，50%(n=17)与任何目标的运动相关联地被类似地调制。剩下的17个神经元表现出相当大的多样性，它们的放电特性与每个靶点的运动有关。如果正确执行，行为的提示阶段总是会得到奖励，而返回阶段永远不会得到奖励。总体而言，这些数据表明，许多GPI神经元以一种上下文相关的方式放电，在有提示的、有奖励的运动中受到调节，但在类似的自我调节、无奖励的运动中没有受到调节。当结合其他观察结果考虑时，我们观察到的上下文依赖似乎很可能受到动物对奖励的期望的影响。
Extracellular discharges from single neurons in the internal segment of the globus pallidus (GPi) were recorded and analyzed for rate changes associated with visually guided forearm rotations to four different targets. We sought to examine how GPi neurons contribute to movement preparation and execution. Unit discharge from 108 GPi neurons recorded in 35 electrode penetrations was aligned to the time of various behavioral events, including the onset of cued and return movements. In total, 39 of 108 GPi neurons (36%) were task-modulated, demonstrating statistically significant changes in discharge rate at various times between the presentation of visual cues and movement generation. Most often, strong modulation in discharge rate occurred selectively during either the cued (n = 32) or return (n = 2) phases of the task, although a few neurons (n = 5) were well-modulated during both movement phases. Of the 34 neurons that were modulated exclusively during cued or return movements, 50% (n = 17) were modulated similarly in association with movements to any target. The remaining 17 neurons exhibited considerable diversity in their discharge properties associated with movements to each target. Cued phases of behavior were always rewarded if executed correctly, whereas return phases were never rewarded. Overall, these data reveal that many GPi neurons discharged in a context-dependent manner, being modulated during cued, rewarded movements, but not during similar self-paced, unrewarded movements. When considered in the light of other observations, the context-dependence we have observed seems likely to be influenced by the animal's expectation of reward.