NEUROPHYSIOLOGY OF ACTION SELECTION IN THE CEREBRAL CORT

本研究的目的是探讨多种潜在运动动作的规范和选择所涉及的大脑皮层机制。这项工作的动机在于一个广泛的理论框架，该框架基于“行动规范”（指定潜在行动的参数）和“行动选择”（在几个可能的行动过程中进行选择）的平行神经机制。在这个框架中，感觉输入的神经处理可以导致几个潜在运动动作的同时规范，其中一个可能被释放到执行（选择）取决于行为背景。在我们的实验中，我们训练一只猴子在一段指示延迟期后对空间目标做出动作，在这段时间里，两个潜在的目标出现了。在指示延迟的前半段，猴子不知道哪个目标是正确的。在下半场，一个非空间提示指示正确的目标。问题是：当猴子还不知道哪一个是正确的动作时，它准备这两个可能的动作有多详细？也就是说，他是仅仅记住目标的感官表征，还是以同样的细节程度准备（指定）两种潜在的运动，就像准备一个明确的运动一样？初步结果支持后一种可能性，支持平行行动规范和选择的框架。

The purpose of the proposed project is to investigate the cerebral cortical mechanisms involved in the specification and selection of multiple potential motor actions. The motivation for this work lies in a broad theoretical framework based on parallel neural mechanisms of "action specification" (which specify the parameters of potential actions) and mechanisms of "action selection" (which choose between several possible courses of action). In this framework, neural processing of sensory input can lead to the simultaneous specification of several potential motor actions, one of which may be released into execution (selected) depending on the behavioral context. In our experiment, we train a monkey to make reaching movements to spatial targets after an instructed delay period during which two potential targets are presented. During the first half of the instructed delay, the monkey does not know which target will be the correct one. During the second half, a non-spatial cue indicates the correct target. The question is: In how much detail does the monkey prepare the two potential movements while he still does not know which will be the correct one? That is, does he merely remember sensory representations of the targets or does he prepare (specify) both potential movements with the same degree of detail with which a single unambiguous movement can be prepared? Preliminary results favor the latter possibility, supporting the framework of parallel action specification and selection.