Abstract
Purpose: Is perceptual space coded in the reference frame of the eye, head, body or space? We moved eyes with respect to head, the head with respect to a stationary body, the body with respect to a stationary head and both the head and body with respect to space to separate the head, body and space frames. Method: Auditory (60L-60R) targets were presented when eyes, head and body were pointing straight ahead. Subjects adjusted the interaural intensity ratio of 1kHz, 15ms sound bursts presented through headphones to indicate the remembered position of these targets relative to the head after actively moving their head, body (with head restrained) or both head and body together. Results: There was a significant shift in localization with head position (0.023db/deg, equivalent to approx. 2.3 deg/deg head rotation in the direction of head eccentricity, p<0.0001). A similar effect was also observed when the head was fixed in space while body position was changed. Moving the eyes with respect to the head, and body and head together had no effect on auditory localization judgments. Conclusions: Perceptual localization requires head-on-body, but not body-in-space information indicating the use of a body reference frame. CR: none. Supported by: Natural Science and Engineering Research Council (NSERC) of Canada and the Centre for Research in Earth and Space Technology (CRESTech) of Canada.