The role of proprioceptive plasticity in movement control
Final Report Abstract
When we move – practically all the time – information on limb position is crucial. Vision provides accurate and precise position information, but it is augmented by a sense of felt hand position, or “proprioception” as well as by a prediction of sensory consequences based on planned movements. When visual feedback is altered, proprioception recalibrates and our lab has previously shown that recalibrated proprioception by itself leads to motor changes as well. Training with altered visual feedback also updates predictions of sensory consequences. Here we focus on the role of proprioception in visuomotor adaptation, and how it relates to updates in predicted sensory consequences in a series of experiments. First we tease apart recalibrated proprioception from predicted sensory consequences and find that after training with rotated feedback, the bulk of the change in hand localization can be explained by recalibrated proprioception. Contrary to our expectations, predicted sensory consequences and recalibrated proprioception are not combined in a maximum likelihood estimate. Second, we test if awareness of the manipulation of the feedback can reduce both proprioceptive recalibration and updating of predicted sensory consequences and if age-related cognitive and sensory decline play a role. We show that awareness of the manipulation has no effect on either proprioception or prediction. However, there is a small increase in proprioceptive recalibration, but not in updating predicted sensory consequences, that could be explained by an age-related decline in the reliability of proprioception. Third, we investigate the time-course of proprioceptive recalibration, and if it can be linked to the two processes from a well-known model of motor learning. We show that proprioception is fully recalibrated after one trial with rotated feedback, and that it’s time-course does not match either process of the model. The time course of updates in predicted sensory consequences – as we estimate it here – doesn’t match these processes either, but more closely follows the change in motor output. All of the results confirm that proprioception is a separate process in motor learning, that needs to be taken into account. To sum up, (recalibrated) proprioception seems to be more important than predicted sensory consequences when estimating hand position. Proprioceptive recalibration is implicit and robust in old age. Recalibration of proprioception might precede all other processes in visuomotor adaptation. These results should inform future studies and models of motor learning.
Publications
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(2016). Separating predicted and perceived sensory consequences of motor learning. PLoS ONE, 11(9): e0163446
’t Hart BM, Henriques DYP
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(2016). Time Course of Reach Adaptation and Proprioceptive Recalibration during Visuomotor Learning. PLoS ONE, 11(10): e0163695
Ruttle JE, Cressman EK, ’t Hart BM, Henriques DYP
