Cortical adaptations and motor performance improvements associated with short-term bimanual training.

Bimanual movement can increase activity within the stroke-affected hemisphere and may contribute to recovery in some patients. To understand how bimanual learning may aid recovery post-stroke, the present study used EEG to investigate cortical adaptations associated with short-term bimanual training and the behavioral modulations that transfer to unimanual movement in healthy individuals. Movement-related potentials (MRP) and reaction times (RT) were recorded from 10 healthy subjects during blocks of unimanual visuomotor trials before and after a bimanual training task. We hypothesized that short-term bimanual practice would induce adaptive cortical changes evident in the MRPs to movements involving a single hand. Post-training results showed that: (1) the late MRP amplitude did not change, (2) RT significantly decreased, and (3) there was a trend for the early MRP amplitude to increase. There was a strong relationship between modulation of early MRP amplitude and RT in the unimanual movement blocks before and after training. Specifically, a subgroup showed a significant decrease in RT in conjunction with a significant increase in the early MRP amplitude. Lastly, comparing later to earlier trials within the bimanual training block, task accuracy and early MRP amplitude significantly increased and (2) a positive re-afferent potential significantly decreased. Results suggest that short-term bimanual training is associated with possible transfer effects to a unimanual task reflected in changes of MRP components and RT. Furthermore, results from the bimanual training trial itself indicate that short-term bimanual training can change the level of motor preparation and sensory feedback in all subjects.