Grant: Project Grant

This project is designed to determine the contribution of one part of the cerebral cortex, known to be involved in the planning of voluntary movements (the premotor cortex) to the planning of visually-guided gait modifications. While locomotion is sometimes thought of as a relatively automatic behavior in which the major function is to produce rhythmical, alternating movements of the limbs, it is actually a highly complex activity requiring cognitive and voluntary control under natural circumstances. On uneven terrain, for example, decisions have to be made about where to make the next step and frequently one plans a sequence of steps to avoid an obstacle. Walking in the street, one must decide how to walk around objects and people and how and when to step on and off a curb. Even indoors, one must navigate the furniture and objects on the floor. These behaviours require processing of visual information about the environment and a means to integrate this information with the immediate and long-term locomotor goals of the subject and the state of the limbs at the time of making the decision (e.g. which limb is in stance and which in swing and how do I adjust gait to most efficiently. or quickly, step over that obstacle). In the current project, I intend to test the hypothesis that the premotor cortex contributes to several essential aspects of goal-directed locomotion, including: decision processes that determine which limb will step over an obstacle; determining the parameters of the gait modification (trajectory and/or muscle activation patterns); and in more complex circumstances determining the sequence of steps required to clear a series of obstacles (e.g. a boulder field on a walking trail).