Effect of unimanual training on contralateral motor overflow in children and adults

Young children and adults performed a rapid unimanual finger‐lifting task. Active hand performance and ipsilateral and contralateral motor overflow were examined using a cross‐hand transfer‐of‐training paradigm. Lateral asymmetries in both the performing hands and overflow hands were investigated. An expected developmental trend was evidenced with children exhibiting more motor overflow than adults. There was also greater overflow evidenced when performing with the left hand than with the right hand in both children and adults. Children evidenced a similar asymmetry in transfer of training, that is, greater transfer of training from the left hand to the right hand than vice versa. The relationship between asymmetries in motor overflow and transfer of training is discussed in terms of cerebral specialization for movement control. Finally, training does seem to influence ipsilateral overflow, suggesting that task efficiency may play a role in the occurrence of motor overflow and that caution be exercised in the use of motor overflow as a diagnostic tool.