Neural Mechanisms Underlying Hand Choice for Unimanual Action

描述（由申请人提供）：我们的长期目标是了解大脑的不同区域如何选择、计划和实施熟练的动作。在目前的提案中，重点是手的选择；人们如何选择一只手或另一只手去接触环境中的物体并与之互动。这个问题每天都会遇到很多次——拿起咖啡杯，打电话，指路时指着一个地标——而且似乎毫不费力就能解决。然而，解决这一简单决策过程的心理过程和神经机制在文献中受到的关注很少。与知觉选择的研究结果类似，我们最近的研究表明，手的选择涉及与选择左手或右手相关的表征之间的竞争过程。到目前为止，我们的工作主要集中在行为上，描述了手选择中涉及的心理和生理过程。在提议的工作中，重点将放在识别与这一基本但基本的决策过程相关的皮层和皮层下区域。为此目的，将处理三个具体目标。1)识别非手动动作中涉及手部选择的神经区域。2)使用强化学习任务直接比较使用反馈的过程，当结果与参与者肢体控制感的变化相关时。作为比较点，手选择任务的数据将与涉及对象选择的更标准的决策任务进行比较。3)识别与手选择和反应启动相关的抑制过程相关的神经区域。实验计划需要综合运用功能成像、脑刺激和神经心理学研究。在这个项目完成时，我们期望不仅在我们对行动选择的理解，而且在我们如何控制和抑制行动方面取得重大进展。

DESCRIPTION (provided by applicant): Our long-range goal is to understand how different regions of the brain select, plan, and implement skilled actions. In the current proposal, the focus is on hand choice; how people select one hand or the other to reach for and interact with objects in the environment. This problem is encountered many times each day-- picking up a coffee cup, using the telephone, pointing to a landmark when giving directions -- and accomplished in a seemingly effortless manner. However, the psychological processes and neural mechanisms engaged in solving this simple decision process have received minimal attention in the literature. Similar to findings in research on perceptual choices, our recent studies demonstrate that hand choice involves a competitive process between representations associated with the selection of the left or right hand. To date, our work has generally focused on behavior, characterizing the psychological and physiological processes involved in hand choice. In the proposed work, the emphasis will be on identifying cortical and subcortical regions associated with this elementary, yet fundamental decision process. To this end, three specific aims will be addressed. 1) Identify the neural regions involved in hand choice during unimanual actions. 2) Use a reinforcement learning task to directly compare processes involving in using feedback when the outcomes are associated with variation in the participant's sense of limb control. As a point of comparison here, the data from the hand choice task will be compared to a more standard decision-making task involving object choice. 3) Identify the neural regions associated with inhibitory processes involved in hand selection and response initiation. The experimental plan entails the integrated use of functional imaging, brain stimulation, and neuropsychological studies. At the completion of this project, we expect to have made significant advances, not only in our understanding of action selection, but also in how we control and inhibit actions.