Minimal impact of chronic proprioceptive loss on implicit sensorimotor adaptation and perceived movement outcome

Implicit sensorimotor adaptation keeps our movements well-calibrated amid changes in the body and environment. We have recently postulated that implicit adaptation is driven by a perceptual error: the difference between the desired and perceived movement outcome. According to this perceptual re-alignment model, implicit adaptation ceases when the perceived movement outcome – a multimodal percept determined by a prior belief conveying the intended action, the motor command, and feedback from proprioception and vision – is aligned with the desired movement outcome. Here, we examined the role of proprioception in implicit motor adaptation and perceived movement outcome by examining individuals who experience deafferentation (i.e., individuals with impaired proprioception and touch). We used a modified visuomotor rotation task designed to isolate implicit adaptation and probe perceived movement outcome throughout the experiment. Surprisingly, both implicit adaptation and perceived movement outcome were minimally impacted by chronic deafferentation, posing a challenge to the perceptual re-alignment model of implicit adaptation.

内隐感觉运动适应（implicit sensorimotor adaptation）可在机体与环境发生变化时，维持运动状态的精准校准。我们近期提出，内隐适应由感知误差驱动：即预期运动结果与感知到的运动结果之间的差值。基于该感知重对齐模型，当感知到的运动结果——这一多模态感知由传递意图动作的先验信念、运动指令以及本体感觉（proprioception）与视觉反馈共同决定——与预期运动结果对齐时，内隐适应便会停止。本研究通过招募存在传入神经阻滞（deafferentation）的个体（即本体感觉与触觉受损的人群），探究了本体感觉在内隐运动适应与感知运动结果中的作用。我们采用了经过改良的视觉运动旋转任务（visuomotor rotation task），该任务旨在分离内隐适应过程，并在整个实验中探测感知到的运动结果。令人意外的是，慢性传入神经阻滞对内隐适应与感知运动结果均几乎无影响，这对内隐适应的感知重对齐模型构成了挑战。