Coordination of Action in Distributed, but Unequal, Bimanual Tasks

University Of California-Davis, Davis CA

Investigators

Abstract

Many activities require our hands to work together but the way they coordinate differs depending on the task. For example, when hammering a nail, one hand must stabilize the nail while the other swings the hammer. When opening a jar, the hands need to exert pressure in different directions and our grip adjusts based on the size and texture of the surface that is gripped. Both these activities require the hands to have different responsibilities and movements, but the hands must cooperate to accomplish the task. This project explores how cooperative bimanual control is learned and how the coordination adjusts when the requirements change. The findings should be informative for rehabilitation after stroke, especially for the many activities of daily living that rely on bimanual asymmetric movements, as well as for optimal design of human-machine interfaces. In addition, planned classroom demonstrations and workshops provide local elementary school students with robotics experiences during the school year and in the summer. Bimanual tasks typically involve an unequal distribution of control, with the two limbs having complementary responsibilities and motor functions. Although there is a growing literature on the neural processes involved when learning new motor patterns using one limb, there is a substantial gap in our understanding of how the two hands coordinate control in accomplishing a single task, particularly when the required motor functions are not the same. The investigators use a novel motor coordination task that requires the two limbs to control different aspects of a single virtual object. This allows them to explore how perturbations of one feature of the coordinated task influence the behavior of the other, unperturbed limb. Other conditions probe the relationships between motor actions and the perception of coordinated control (i.e., the sense of agency). By quantifying these changes in behavior, these studies provide a deeper understanding of how we accomplish daily activities that require different, but synchronized motor functions from the two hands (e.g., chopping food, fastening buttons, etc.) and will provide a foundation for studying how the brain controls bimanual actions. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.