Ingram H A, van Donkelaar P, Cole J, Vercher J L, Gauthier G M, Miall R C
University Laboratory of Physiology, Oxford, UK.
Exp Brain Res. 2000 May;132(1):114-26. doi: 10.1007/s002219900322.
The role of proprioception in the control and adaptation of visuomotor relationships is still unclear. We have studied a deafferented subject, IW, and control subjects in a task in which they used single joint elbow extension to move to a visual target, with visual feedback of the terminal position provided by a cursor displayed in the plane of their movements. We report the differences in movement accuracy between the deafferented subject and controls in the normal task and when challenged with a cognitive load, counting backwards. All subjects were less accurate when counting; this was a small effect for the controls (<10% change) but much greater for the deafferented subject (>60% change). We also examined changes in movement kinematics when the instructed amplitude was altered via a changed gain between final arm position and presentation of the feedback cursor. The deafferented subject maintained temporal movement parameters stable and altered amplitude by scaling force (i.e. changed peak velocity), whereas the controls scaled both movement velocity and duration. Finally, we compared the subjects' adaptation of movement amplitude after a period of exposure to the changed visuomotor gain. The deafferented subject was able to adapt, but his adaptation was severely impaired by the counting task. These results suggest that proprioception is not an absolute requirement for adaptation to occur. Instead, proprioception has a more subtle role to play in the adjustment to visuomotor perturbations. It has an important role in the control of reaching movements, while in the absence of proprioception, attention appears necessary to monitor movements.
本体感觉在视觉运动关系的控制和适应中的作用仍不明确。我们研究了一名去传入神经的受试者IW以及对照受试者，他们执行一项任务，即通过单关节肘部伸展动作移向一个视觉目标，在其运动平面上显示的光标会提供末端位置的视觉反馈。我们报告了在正常任务以及面临认知负荷（倒数）挑战时，去传入神经的受试者与对照受试者在运动准确性上的差异。所有受试者在倒数时准确性都会降低；这对对照受试者的影响较小（变化<10%），但对去传入神经的受试者影响更大（变化>60%）。我们还研究了通过改变最终手臂位置与反馈光标呈现之间的增益来改变指令幅度时，运动运动学的变化。去传入神经的受试者保持时间运动参数稳定，并通过缩放力（即改变峰值速度）来改变幅度，而对照受试者则同时缩放运动速度和持续时间。最后，我们比较了受试者在一段时期暴露于改变后的视觉运动增益后对运动幅度的适应情况。去传入神经的受试者能够适应，但计数任务严重损害了他的适应能力。这些结果表明，本体感觉并非适应发生的绝对必要条件。相反，本体感觉在对视觉运动扰动的调整中起着更为微妙的作用。它在控制伸手动作中具有重要作用，而在没有本体感觉的情况下，注意力似乎对于监测动作是必要的。
