![]() ![]() Data are from the same observers and visual field locations shown in Figure 2. Motion-in-depth discrimination based on monocular cues. Example stimuli are shown in the Supplementary Movies. The number of dots, their sizes, and the depicted optic flow patterns used in the schematics were selected to convey the MID cues, rather than portray the actual stimuli. Noise dots (depicted here as open circles) moved to random locations, producing motion signals of random speed and direction. Signal dots (depicted here as filled black dots) moved either toward or away from the observer. (E) Stimulus coherence: Stimuli were presented at five motion coherences (proportion of signal dots: 0.08, 0.25, 0.50, 0.75, and 1). After responding, there was an inter-trial interval of 750 ms. (D) Temporal sequence: Stimuli were presented for 250 ms. Combined cue stimuli were optic flow patterns shown to both eyes, and thus contained both cues. Monocular cue stimuli were optic flow patterns shown to one eye. Binocular cue stimuli contained opposite horizontal motions in the two eyes. (C) Cue conditions: On each trial, one of three cue conditions was presented. A 1/f noise background pattern facilitated stable version and vergence. Observers fixated a central target (a white dot). (B) Visual stimulus: On each trial, a stimulus appeared in one aperture (e.g., the one outlined in red for illustration). Observers reported the perceived motion direction (toward/away). Stimuli depicted dots moving in depth through a cylindrical volume oriented perpendicular to the display. (A) Experimental design: Observers viewed a visual display through 3D shutter glasses. Schematic of the display, stimulus, and conditions. These results reveal distinct factors constraining the contributions of binocular and monocular cues to three-dimensional motion perception. Finally, contralateral monocular cue sensitivity was found to be a strong predictor of combined cue sensitivity. Third, we found that monocular cue sensitivity generally exceeded, and was independent of, binocular cue sensitivity. This resulted in better monocular discrimination performance when the contralateral rather than ipsilateral eye was stimulated. A major component of this variability was geometric: An MID stimulus produces the largest motion signals in the eye contralateral to its visual field location. Second, we determined that monocular MID cue sensitivity also varied considerably across the visual field. The stimuli were matched for eccentricity and speed, suggesting that this variability has a neural basis. ![]() We first confirmed prior reports of substantial variability in binocular MID cue sensitivity across the visual field. Here we measured sensitivity to binocular, monocular, and combined cue MID stimuli using a motion coherence paradigm. Because previous studies largely characterized sensitivity to these cues individually, their relative contributions to MID perception remain unclear. Such motion can be estimated based on both binocular and monocular cues. Intercepting and avoiding moving objects requires accurate motion-in-depth (MID) perception.
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