School of Kinesiology and Health Science, York University, Toronto, Ontario, Canada.
J Neurophysiol. 2013 Aug;110(4):952-63. doi: 10.1152/jn.00764.2012. Epub 2013 May 22.
The aim of this research was to understand how the brain controls voluntary movement when not directly interacting with the object of interest. In the present study, we examined the role of premotor cortex in this behavior. The goal of this study was to characterize the oscillatory activity within the caudal and rostral subdivisions of dorsal premotor cortex (PMdc and PMdr) with a change from the most basic reaching movement to one that involves a simple dissociation between the actions of the eyes and hand. We were specifically interested in how PMdr and PMdc respond when the eyes and hand are decoupled by moving along different spatial planes. We recorded single-unit activity and local field potentials within PMdr and PMdc from two rhesus macaques during performance of two types of visually guided reaches. During the standard condition, a visually guided reach was performed whereby the visual stimulus guiding the movement was the target of the reach itself. During the nonstandard condition, the visual stimulus provided information about the direction of the required movement but was not the target of the motor output. We observed distinct task-related and topographical differences between PMdr and PMdc. Our results support functional differences between PMdr and PMdc during visually guided reaching. PMdr activity appears more involved in integrating the rule-based aspects of a visually guided reach, whereas PMdc is more involved in the online updating of the decoupled reach. More broadly, our results highlight the necessity of accounting for the nonstandard nature of a motor task when interpreting movement control research data.
本研究旨在探讨大脑在不直接与感兴趣的物体相互作用的情况下如何控制自主运动。在本研究中，我们研究了运动前皮层在这种行为中的作用。本研究的目的是描述尾侧和头侧背侧运动前皮层（PMdc 和 PMdr）的振荡活动，从最基本的伸手运动转变为涉及眼睛和手简单分离的运动。我们特别感兴趣的是，当眼睛和手沿着不同的空间平面移动时，PMdr 和 PMdc 是如何做出反应的。我们在两只恒河猴执行两种视觉引导伸手运动时，记录了 PMdr 和 PMdc 中的单个单元活动和局部场电位。在标准条件下，执行视觉引导伸手运动，引导运动的视觉刺激是伸手运动的目标。在非标准条件下，视觉刺激提供了所需运动方向的信息，但不是运动输出的目标。我们观察到 PMdr 和 PMdc 之间存在明显的与任务相关的和地形学上的差异。我们的结果支持视觉引导伸手运动中 PMdr 和 PMdc 之间的功能差异。PMdr 活动似乎更参与整合基于规则的视觉引导伸手运动的方面，而 PMdc 更参与解耦伸手运动的在线更新。更广泛地说，我们的结果强调了在解释运动控制研究数据时，必须考虑运动任务的非标准性质。
