Title: “Investigating the central and peripheral contributions to tactile gating during goal-directed movement”
Supervisor: Dr. Romeo Chua (Kinesiology)
Committee Members: Dr. Tim Inglis (Kinesiology), Dr. Ian Franks (Kinesiology)
Abstract: The current thesis proposal will focus on the facilitation and downregulation of sensory information during goal-directed movement. Specifically, the presence or absence of tactile gating, in which humans display a reduced ability to detect tactile stimulations on the skin before and during active or passive movement, will be explored. Recent findings suggest that the CNS selectively attenuates tactile information if it is presented to a task irrelevant location on the moving limb. Further, tactile information will not be attenuated if it is presented at a task relevant location. In turn, central and peripheral processes have been thought to contribute to tactile gating but the existing literature has failed to directly isolate these mechanisms during goal-directed movement. This thesis will therefore explore the contributions to tactile gating by isolating central and peripheral processes during goal-directed movement.
In this thesis, participants will perform variations of a reach to grasp movement. In addition to a normal or unperturbed reach to grasp, participants will try to perform the task but will be unexpectedly blocked at movement start. In another condition, participants will be passively guided throughout the task. These additional conditions will allow for the isolation of central and peripheral commands, respectively. Prior to or during movement, participants will receive an innocuous electrical stimulation to the thumb, index finger or forearm. In this case, the thumb and index finger act as task relevant locations on the moving limb whereas the forearm acts as the task irrelevant location. In turn, their ability to detect this tactile stimulation will allow for inferences to be made in regards to the relative contribution of central and peripheral mechanisms to tactile gating.