Reaches to sounds encoded in an eye-centered reference frame

A recent hypothesis suggests that neurons in the lateral intraparietal area (LIP) and the parietal reach region (PRR) encode movement plans in a commo n eye-centered reference frame. To test this hypothesis further, we examine d how PRR neurons encode reach plans to auditory stimuli. We found that PRR activity was affected by eye and initial hand position. Population analyse s, however, indicated that PRR neurons were affected more strongly by eye p osition than by initial hand position. These eye position effects were appr opriate to maintain coding in eye coordinates. Indeed, a significant popula tion of PRR neurons encoded reaches to auditory stimuli in an eye-centered reference frame. These results extend the hypothesis that, regardless of th e modality of the sensory input or the eventual action, PRR and LIP neurons represent movement plans in a common, eye-centered representation.