Eye position and cross-sensory learning both contribute to prism adaptation of auditory space.
Optical prisms shift visual space, and through adaptation over time, generate a compensatory realignment of sensory-motor reference frames. In humans, prism-induced lateral shifts of visual space produce a corresponding shift in sound localization. We recently reported that sound localization shifts towards eccentric eye position, approaching approximately 40% of gaze over several minutes. Given that eye position affects sound localization directly, prism adaptation may well reflect contributions of both eye position and sensory adaptation; while the visual world is shifted by the prisms, the eyes must also shift simply to gaze ahead. To test this new concept of prism adaptation, 10 young (18-27 year) adults localized sound targets before and after 4 h of adaptation to base-right or base-left prisms that induced an 11.4 degrees shift left or right, respectively. In separate sessions subjects were exposed to: (1) natural binaural hearing; (2) diotically presented inputs devoid of meaningful spatial cues; or (3) attenuated hearing to simulate hearing loss. These preliminary results suggest that the prism adaptation of auditory space is dependent on two independent influences: (1) the effect of displaced mean eye position induced by the prisms, which occurs without cross-sensory experience; and (2) true cross-sensory learning in response to an imposed offset between auditory and visual space.
Cui
Qi N
QN
Department of Neurobiology and Anatomy, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA.
Bachus
Laura
L
Knoth
Eva
E
O'Neill
William E
WE
Paige
Gary D
GD
D000222:Adaptation, Physiological / Q000502:physiology*; D000328:Adult; D000818:Animals; D005133:Eye Movements / Q000502:physiology; D005260:Female; D006801:Humans; D007858:Learning / Q000502:physiology*; D008297:Male; D010468:Perceptual Disorders / Q000503:physiopathology; D011597:Psychomotor Performance; D013017:Sound Localization / Q000502:physiology*; D013028:Space Perception / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*; D055815:Young Adult