Biomedical Engineering, Marquette University and Medical College of Wisconsin, Olin Engineering Center Rm 206, 1515 W. Wisconsin Ave, Milwaukee, WI, 53233, USA.
Psychology, Marquette University and Neurology, Medical College of Wisconsin, Milwaukee, WI, 53233, USA.
Exp Brain Res. 2023 Jan;241(1):231-247. doi: 10.1007/s00221-022-06515-3. Epub 2022 Dec 5.
We examined a key aspect of sensorimotor skill: the capability to correct performance errors that arise mid-movement. Participants grasped the handle of a robot that imposed a nominal viscous resistance to hand movement. They watched a target move pseudo-randomly just above the horizontal plane of hand motion and initiated quick interception movements when cued. On some trials, the robot's viscosity or the target's speed changed without warning coincident with the GO cue. We fit a sum-of-Gaussians model to mechanical power measured at the handle to determine the number, magnitude, and relative timing of submovements occurring in each interception attempt. When a single submovement successfully intercepted the target, capture times averaged 410 ms. Sometimes, two or more submovements were required. Initial error corrections typically occurred before feedback could indicate the target had been captured or missed. Error corrections occurred sooner after movement onset in response to mechanical viscosity increases (at 154 ms) than to unprovoked errors on control trials (215 ms). Corrections occurred later (272 ms) in response to viscosity decreases. The latency of corrections for target speed changes did not differ from those in control trials. Remarkably, these early error corrections accommodated the altered testing conditions; speed/viscosity increases elicited more vigorous corrections than in control trials with unprovoked errors; speed/viscosity decreases elicited less vigorous corrections. These results suggest that the brain monitors and predicts the outcome of evolving movements, rapidly infers causes of mid-movement errors, and plans and executes corrections-all within 300 ms of movement onset.
即在运动过程中纠正表现错误的能力。参与者握住机器人的手柄，机器人对手的运动施加名义粘性阻力。他们观看一个目标在手部运动的水平平面上方以伪随机方式移动，并在收到提示时快速进行拦截动作。在某些试验中，机器人的粘性或目标的速度会在 GO 提示时突然改变，而没有任何警告。我们拟合了手柄处测量的机械功率的高斯和模型，以确定每次拦截尝试中发生的子运动的数量、幅度和相对时间。当单个子运动成功拦截目标时，捕获时间平均为 410ms。有时，需要两个或更多的子运动。在反馈可以指示目标已捕获或错过之前，通常会在初始错误之前进行错误校正。与控制试验中的无端错误相比（215ms），机械粘性增加时（在 154ms），错误校正更早发生。响应粘度降低时，校正发生得更晚（272ms）。响应目标速度变化的校正潜伏期与控制试验中的校正潜伏期没有差异。值得注意的是，这些早期错误校正适应了改变的测试条件；速度/粘性增加比在控制试验中无端错误引起的校正更剧烈；速度/粘性降低引起的校正不太剧烈。这些结果表明，大脑监测和预测不断发展的运动的结果，快速推断运动过程中错误的原因，并在运动开始后 300 毫秒内计划和执行校正。
