Recent
motor control theories suggest that
the brain uses internal models to
plan and control
accurate movements. An internal model is thought to represent how the biomechanics of the
arm interacting with the outside world would respond to a motor command; therefore it can be seen as a predictive model of the reafference that helps the system
plan ahead. Moreover, adaptation studies show that humans can learn multiple internal models. It is not clear, however, whether and how contextual cues are used to switch among competing internal models, which are required to compensate for altered environments. To investigate this question, we asked healthy participants to perform center-out pointing movements under normal and distorted
visual feedback (0 degrees , 30 degrees counterclockwise, and 60 degrees clockwise rotation of hand-screen cursor relationships) conditions. The results suggest that humans can learn multiple environments simultaneously and can use contextual cues to facilitate adaptation and to recall the appropriate internal model of the visuomotor transformation.
