Motor learning transfer from isometric to dynamic reaching

After unilateral stroke, physical impairment commonly appears on one side of the body. As the unaffected side is the non-dominant side for some patients, we investigated whether human motor learning can transfer from a non-dominant arm to the dominant, with a 2-dof manipulandum that allows both isometric and dynamic reaching. The goal of our study was to assess the transfer of visuomotor adaptation from a non-dominant arm, trained in an isometric condition, to a dominant arm, freely moving in a dynamic condition. Previous studies have found how the human motor system adapts to visual rotation, after which hand paths curve even in the absence of rotation. Some of the studies have shown how interlimb transfer of adaptation occurs for a dynamic condition. We observed that participants could adapt to visual rotation in an isometric condition with velocity control and show aftereffect in the dynamic condition with the opposite arm. Our result confirms previous research that environmental information is stored and can be accessed by both limbs. In addition, we found evidence that such information can be learned in an isometric condition and accessed in a dynamic condition.