Staying in Tune

When performing daily life activities, appropriate sensory-motor transformations are required to successfully map the changing relationships among one´s self, the environment, and objects moving in the environment. Our daily actions involve varying combinations of head-eye (gaze), arm-reaching, and whole-body (stepping and walking) movements. These movements depend on the interaction and transformation of both egocentric (self to object) and allocentric (object to object) representations of the environment. To successfully map these representations, appropriate sensory-motor transformations are required. For visually guided movements, the primary motor cortex and its interactions with the visual cortex, mainly through the dorsal stream, are largely responsible for mapping the sensory-motor actions. Many uncontrollable factors can contribute to the degradation of our balance system; hence, it is important to maintain or retrain our sensory- motor system. In this article, the position of a visible computer sprite is controlled through the movement of the center of foot pressure (COP), which changes when a person produces body sway. The visually guided movements of the COP require timely sensory-motor mappings of visually derived spatial information acquired in a two-dimensional (2D) virtual environment, i.e., sprite location relative to a target position.