Computational and Biological Learning Laboratory, Department of Engineering, University of Cambridge, Cambridge CB2 1PZ, UK.
J Neurosci. 2012 Feb 15;32(7):2276-86. doi: 10.1523/JNEUROSCI.5273-11.2012.
Both decision making and sensorimotor control require real-time processing of noisy information streams. Historically these processes were thought to operate sequentially: cognitive processing leads to a decision, and the outcome is passed to the motor system to be converted into action. Recently, it has been suggested that the decision process may provide a continuous flow of information to the motor system, allowing it to prepare in a graded fashion for the probable outcome. Such continuous flow is supported by electrophysiology in nonhuman primates. Here we provide direct evidence for the continuous flow of an evolving decision variable to the motor system in humans. Subjects viewed a dynamic random dot display and were asked to indicate their decision about direction by moving a handle to one of two targets. We probed the state of the motor system by perturbing the arm at random times during decision formation. Reflex gains were modulated by the strength and duration of motion, reflecting the accumulated evidence in support of the evolving decision. The magnitude and variance of these gains tracked a decision variable that explained the subject's decision accuracy. The findings support a continuous process linking the evolving computations associated with decision making and sensorimotor control.
决策和感觉运动控制都需要实时处理嘈杂的信息流。历史上，这些过程被认为是按顺序进行的：认知处理导致决策，然后将结果传递给运动系统以转化为行动。最近，有人提出决策过程可能为运动系统提供信息流的连续流动，从而允许其以分级的方式为可能的结果做好准备。这种连续的流动得到了非人类灵长类动物的电生理学支持。在这里，我们为人类运动系统中不断演变的决策变量的连续流动提供了直接证据。受试者观察动态随机点显示，并通过将手柄移动到两个目标之一来指示他们对方向的决定。我们通过在决策形成过程中随机时间干扰手臂来探测运动系统的状态。反射增益受到运动的强度和持续时间的调制，反映了支持不断发展的决策的累积证据。这些增益的幅度和方差跟踪一个决策变量，该变量解释了受试者的决策准确性。这些发现支持了一个连续的过程，将与决策和感觉运动控制相关的不断发展的计算联系起来。
