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.