Grant: Operating Grant

Humans are able to perform a broad range of motor skills, from the rapid spinning of an elite diver to the precise staccato of a violinist. Recent theories suggest that sensory feedback from the limb (and vision) are essential for performing these voluntary motor skills. In particular, the theory suggests feedback is always present and that the properties of the arm and the movement goal influence the use of this feedback for controlling the limb. Our recent studies on humans show how feedback from the limb is used to modify and correct perturbations (unexpected bumps applied to the limb) during reaching or other motor tasks. The timing of these corrections suggest that they are generated from signals transmitted down to the spinal cord from primary motor cortex. Primary motor cortex is known to be important for voluntary control, but its use of feedback for control is not well recognized nor understood. The present proposal will highlight how feedback to this brain region scales with perturbation magnitude, interacts with spinal activity and importantly is modified based on the behavioural goal. This research will change our view on how primary motor cortex controls movement by emphasizing the importance of sensory feedback. This knowledge provides a foundation for understanding how various neurological disorders such as stroke impact brain function and motor performance. The behavioural tasks used in this proposal will also be used in parallel studies to quantify motor deficits in various patient groups.