Neural Correlates of Biased Competition in Premotor Cortex
Neural Correlates of Biased Competition in Premotor Cortex
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DOI：
10.1523/jneurosci.5681-10.2011
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发表时间：
2011-05-11
影响因子：
5.3
通讯作者：
Cisek, Paul
中科院分区：
文献类型：
--
作者：
Pastor-Bernier, Alexandre;Cisek, Paul
有人提出，每当动物面临几个动作选择时，它们的神经表征在额顶叶皮层中并行处理，并以一种受任何与决策相关的因素影响的方式进行竞争。我们测试了这一假设，记录在背运动前皮层（PMD）的单单位活动，而猴子执行两个延迟中心外达到的任务。在单目标任务中，呈现单个目标，其边界样式表示其奖励值。两个目标任务是相同的，除了两个目标，每个目标的价值是不同的。在延迟期的一个目标任务，定向调谐PMd活动没有表现出调制值。相比之下，在两个目标任务中，相同的神经元表现出与其首选目标相关的价值的强烈影响，总是与另一个目标的价值有关。此外，当目标距离最远时，行动选择之间的竞争最强。这种角距离效应在神经活动中出现时，细胞已经被调谐，而相对值的调制则出现得更晚。所有这些发现都可以通过一个计算模型来重现，该模型表明，动作之间的决定是通过在潜在动作的感觉运动图中发生的有偏见的竞争来做出的。
It has been proposed that whenever an animal faces several action choices, their neural representations are processed in parallel in frontoparietal cortex and compete in a manner biased by any factor relevant to the decision. We tested this hypothesis by recording single-unit activity in dorsal premotor cortex (PMd) while a monkey performed two delayed center-out reaching tasks. In the one-target task, a single target was presented and its border style indicated its reward value. The two-target task was the same except two targets were presented and the value of each was varied. During the delay period of the one-target task, directionally tuned PMd activity showed no modulation with value. In contrast, during the two-target task, the same neurons showed strong effects of the value associated with their preferred target, always in relation to the value of the other target. Furthermore, the competition between action choices was strongest when targets were furthest apart. This angular distance effect appeared in neural activity as soon as cells became tuned, while modulation by relative value appeared much later. All of these findings can be reproduced by a computational model which suggests that decisions between actions are made through a biased competition taking place within a sensorimotor map of potential actions.