ABSTRACT
It is hypothesized that the organization of limb movements involves a series of sensorimotor transformations: between intrinsic and extrinsic coordinates, between the intrinsic coordinates and dynamics, and between dynamics and muscle activation. It is also hypothesized that these transformations involve approximations and the imposition of constraints that lead to uniqueness of behavior. This chapter focuses on the first of these transformations. Data from psychophysical experiments are summarized. These experiments were designed to lead to the identification of a preferred coordinate representation of the intrinsic frame of reference of the arm and the characteristics of the mapping between points in the extrinsic and intrinsic frames of reference. Results of experiments that gave insight into the algorithm whereby wrist motion in arbitrary planes in space could be produced are also summarized. The results are consistent with implementations that involve approximations in the mappings between intrinsic and extrinsic parameter spaces.
