Proprioception contributes to learning of a continuous motor sequence

Abstract

The role of proprioception in skill acquisition is unclear. Current theories of motor control postulate a role for proprioceptive feedback early in the development of a skill, i.e. cognitive and associative phases of learning. The current study sought to better characterize the importance of proprioceptive feedback in motor learning. It was hypothesized that disruption of proprioceptive feedback by vibration would diminish sequence learning. Vibration has been shown to disrupt dynamic intrafusal afferents, resulting in poor conscious awareness of limb position and translation. Two groups of healthy adults participated in a continuous tracking task using their dominant upper extremity. The IPSI group (n=4) received vibration to their dominant shoulder during the task. The CONTRA (n=4) group received vibration to their non-dominant shoulder. Both groups continuously tracked 10 blocks of 10 waveforms over several days. Regularly embedded in target waveforms was a 15s repeated epoch. All subjects returned on a separate day to participate in a no-vibration retention test. For this preliminary report, normalized root mean squared deviation (RMSE) change scores were calculated for each repeated epoch. T-testing indicated a trend toward decreased RMSE on retention for CONTRA (p=0.055). Previous work has demonstrated limited importance of proprioceptive feedback in movement performance. Consistent with our hypothesis, it appears that proprioception may play a role in learning the regularities of a motor sequence. Future studies will examine the impact of damage to central sensory processing structures, such as cortical or cerebellar stroke, on motor learning.