title: Disparity-tuned channels of the human visual system.
abstract: Traditionally, it has been thought that the processing of binocular disparity for the perception of stereoscopic depth is accomplished via three types of disparity-selective channels--"near," "far," and "tuned." More recent evidence challenges this notion. We have derived disparity-tuning functions psychophysically using a subthreshold summation (i.e. low-level masking) technique. We measured correlation-detection thresholds for dynamic random-element stereograms containing either one or two surfaces in depth. The resulting disparity-tuning functions show an opponent-type profile, indicating the presence of inhibition between disparity-tuned units in the visual system. Moreover, there is clear inhibition between disparities of the same sign, obviating a strict adherence to near-far opponency. These results compare favorably with tuning functions derived psychophysically using an adaptation technique, and with the tuning profiles from published single-unit recordings. Our results suggests a continuum of overlapping disparity-tuned channels, which is consistent with recent physiological evidence as well as models based on other psychophysical data.
authors.affiliation: Department of Psychology, University of Texas, Austin 78712.
authors.forename: L K
authors.initials: LK
authors.lastname: Cormack
authors.forename: S B
authors.initials: SB
authors.lastname: Stevenson
authors.forename: C M
authors.initials: CM
authors.lastname: Schor
mesh_terms: D003867:Depth Perception / Q000502:physiology*; D006801:Humans; D008433:Mathematics; D011601:Psychophysics; D012684:Sensory Thresholds; D015357:Vision Disparity / Q000502:physiology*; D014795:Visual Pathways / Q000502:physiology*