Investigating implicit sensorimotor adaptation in a bimanual aiming task


Sensorimotor adaptation is the process by which the brain adapts to our constantly changing environment and consists of both explicit and implicit processes. Recent models of implicit sensorimotor adaptation have focused on the realignment of the sensed hand position (Tsay et al., 2022). However, in many situations individuals must adapt to environments that do not require the control of the hand in space, but instead require the manipulation of an object or tool with both hands. Previous work has demonstrated that in a visuomotor rotation protocol that used a bimanual aiming task, there are both explicit and implicit components to the overall adaptation (Eschelmuller et al., 2023). The purpose of this project was to examine implicit sensorimotor adaptation during a bimanual aiming task, which required the control of an integrated cursor. The cursor position was determined by the angle of each elbow but did not directly correspond to the actual hand position. Participants had to move this cursor to a series of targets during error clamped visual feedback, which is thought to investigate only the implicit component of sensorimotor adaptation. Our results indicate that participants started adapting their movements away from the clamped visual feedback, reflecting implicit adaptation to the error clamp. In this task the actual hand position does not align directly with the cursor and therefore, these data indicate that the realignment process may not be directly coupled to the actual position of the hand, but instead involves a realignment of an expected end-effector position.