Effect of Task Constraints on Motor Control of Pointing

University Of Delaware, Newark DE

Investigators

Abstract

When humans reach to grasp an object, many different combinations of muscles and joints can be used than are strictly necessary to achieve accurate hand motion and final hand placement. Thus, when reaching to the same location, two general strategies are possible: a) choose one set of joint motions and use the same set every time, or b) use a range of different joint motions, each of which takes the hand to the same location. Using multiple, equivalent (i.e., in terms of the goal), joint combinations confers advantages under special circumstances, such as when a movement is unexpectedly disturbed. Scientists do not know the extent to which the nervous system uses this strategy during routine tasks. This project will address this question by studying reaching and pointing to target locations throughout the workspace. Motion of the arm and hand will be measured using high-speed video analysis. The experiments are designed to understand how factors such as the subject's level of skill, the presence or absence of vision, and the direction and curvature of the reach, influence which strategy is used. Formal modeling of the nervous system's control of reaching will be used to help explain the experimental results and generate predictions for future work.