Sensorimotor adaptation error signals are derived from realistic predictions of movement outcomes.
Sensorimotor adaptation error signals are derived from realistic predictions of movement outcomes.
复制标题
感觉运动适应误差信号源自对运动结果的实际预测。
DOI：
10.1152/jn.00394.2010
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发表时间：
2011
影响因子：
2.5
通讯作者：
Shelhamer,Mark
中科院分区：
文献类型：
--
作者：
Wong,AaronL;Shelhamer,Mark
控制运动的神经系统通过根据错误自适应地改变电机命令来保持准确性。人们通常认为，驱动适应的错误信号等同于运动结束时观察到的感觉错误；对于眼跳，这通常是视觉(视网膜)错误。然而，我们建议将自适应误差信号作为观察到的视觉误差和对运动结果的真实预测之间的差值来推导。在人类受试者中使用一种改进的眼跳适应任务，我们通过向后推目标来精确地控制在运动结束时经历的错误量，从而使扫视是高度测量的(正视网膜误差)，但比目标没有移动时的高测量要少(视网膜误差比预期的小)。这将预测误差从视觉误差和运动校正中分离出来。尽管有正的视觉误差和前向运动矫正，我们发现眼跳幅度的适应性降低，这一发现可以通过使用基于预测的误差信号得到很好的解释。此外，运动大小的适应性变化与预测和观察到的运动结果之间的差异呈线性相关，这与运动学习的前向模型假说一致，该假说指出，适应误差信号包括使用运动命令的副本(传出副本)计算的运动结果的预测。
Neural systems that control movement maintain accuracy by adaptively altering motor commands in response to errors. It is often assumed that the error signal that drives adaptation is equivalent to the sensory error observed at the conclusion of a movement; for saccades, this is typically the visual (retinal) error. However, we instead propose that the adaptation error signal is derived as the difference between the observed visual error and a realistic prediction of movement outcome. Using a modified saccade-adaptation task in human subjects, we precisely controlled the amount of error experienced at the conclusion of a movement by back-stepping the target so that the saccade is hypometric (positive retinal error), but less hypometric than if the target had not moved (smaller retinal error than expected). This separates prediction error from both visual errors and motor corrections. Despite positive visual errors and forward-directed motor corrections, we found an adaptive decrease in saccade amplitudes, a finding that is well-explained by the employment of a prediction-based error signal. Furthermore, adaptive changes in movement size were linearly correlated to the disparity between the predicted and observed movement outcomes, in agreement with the forward-model hypothesis of motor learning, which states that adaptation error signals incorporate predictions of motor outcomes computed using a copy of the motor command (efference copy).