Minimal impact of proprioceptive loss on implicit sensorimotor adaptation and kinesthetic shift

AbstractImplicit 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 kinesthetic error: the difference between the desired and perceived hand position. According to this kinesthetic re-alignment model, implicit adaptation ceases when the perceived hand position – a multimodal percept determined by a prior belief conveying the intended action, the motor command, and feedback from proprioception and vision – becomes aligned with the desired hand position. Here, we studied the role of proprioception in implicit adaptation and kinesthetic perception by examining individuals who lack proprioception. We used a modified visuomotor rotation task designed to isolate implicit adaptation and probe perceived hand position throughout the experiment. Strikingly, both implicit adaptation and a kinesthetic shift toward the visual perturbation were preserved (but not heightened) in deafferented individuals. While these results provide additional constraints to the kinesthetic re-alignment model, they underscore the minimal impact of proprioceptive loss on implicit adaptation and kinesthetic shift.