Dynamic changes in the cortico-subcortical network during early motor learning

Failure of early motor learning due to damage in any brain area involved in this process may interfere with successful rehabilitation of such patients.

We investigated the changes in activation of the motor network during sequential finger motor learning to delineate the characteristics of the cortico-subcortical network during motor skill learning.

Twenty healthy, right-handed volunteers participated. Subjects were instructed to perform eight blocks of a sequential finger motor task while functional MRI (fMRI) was performed.

The participants had an improvement in performance over time from block 1 to block 4, indicating that successful learning had occurred, followed by a plateau from block 5 to the last block. On fMRI, activities of the contralateral primary sensorimotor cortex, the premotor cortex, the supplementary motor area, and the posterior parietal cortex gradually increased from block 1 to block 4 and then decreased from block 5 to the last. In contrast, activity of the ipsilateral cerebellum showed a linear increase spanning the last block with peak activation. The thalamus and basal ganglia showed unilateral or bilateral activities at the unique stage of motor learning.

These findings delineated the characteristic plastic changes and different roles of the cortico-subcortical network during the early phase of motor learning and automatization.