title: Motion parallax thresholds for unambiguous depth perception.
abstract: The perception of unambiguous depth from motion parallax arises from the neural integration of retinal image motion and extra-retinal eye movement signals. It is only recently that these parameters have been articulated in the form of the motion/pursuit ratio. In the current study, we explored the lower limits of the parameter space in which observers could accurately perform near/far relative depth-sign discriminations for a translating random-dot stimulus. Stationary observers pursued a translating random dot stimulus containing relative image motion. Their task was to indicate the location of the peak in an approximate square-wave stimulus. We measured thresholds for depth from motion parallax, quantified as motion/pursuit ratios, as well as lower motion thresholds and pursuit accuracy. Depth thresholds were relatively stable at pursuit velocities 5-20 deg/s, and increased at lower and higher velocities. The pattern of results indicates that minimum motion/pursuit ratios are limited by motion and pursuit signals, both independently and in combination with each other. At low and high pursuit velocities, depth thresholds were limited by inaccurate pursuit signals. At moderate pursuit velocities, depth thresholds were limited by motion signals.
authors.affiliation: Center for Visual and Cognitive Neuroscience, Department of Psychology, North Dakota State University, P.O. Box 6050, Fargo, ND 58108-6050, United States.
authors.forename: Jessica
authors.initials: J
authors.lastname: Holmin
authors.affiliation: Center for Visual and Cognitive Neuroscience, Department of Psychology, North Dakota State University, P.O. Box 6050, Fargo, ND 58108-6050, United States. Electronic address: mark.nawrot@ndsu.edu.
authors.forename: Mark
authors.initials: M
authors.lastname: Nawrot
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D003867:Depth Perception / Q000502:physiology*; D005260:Female; D005403:Fixation, Ocular / Q000502:physiology; D006801:Humans; D008297:Male; D009039:Motion Perception / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods; D011601:Psychophysics; D011698:Pursuit, Smooth / Q000502:physiology*; D012684:Sensory Thresholds / Q000502:physiology; D015357:Vision Disparity / Q000502:physiology; D015348:Vision, Binocular / Q000502:physiology; D055815:Young Adult
keywords: Depth perception; Depth thresholds; Motion parallax; Motion perception; Smooth pursuit eye movements