Smooth Pursuit of a Partially Occluded Object

There has long been qualitative evidence that humans can pursue an object defined only by the motion of its parts (eg Steinbach, 1976 Vision Research16 1371 – 1375). We explored this quantitatively using an occluded diamond stimulus (Lorenceau and Shiffrar, 1992 Vision Research32 263 – 275). Four subjects (one naive) tracked a line-figure diamond moving along an elliptical path (0.9 Hz) either clockwise (CW) or counterclockwise (CCW) behind either an X-shaped aperture (CROSS) or two vertical rectangular apertures (BARS), which obscured the corners. Although the stimulus consisted of only four line segments (108 cd m−2), moving within a visible aperture (0.2 cd m−2) behind a foreground (38 cd m−2), it is largely perceived as a coherently moving diamond. The intersaccadic portions of eye-position traces were fitted with sinusoids. All subjects tracked object motion with considerable temporal accuracy. The mean phase lag was 5°/6° (CROSS/BARS) and the mean relative phase between the horizontal and vertical components was +95°/+92° (CW) and −85°/−75° (CCW), which is close to perfect. Furthermore, a \chi2 analysis showed that 56% of BARS trials were consistent with tracking the correct elliptical shape ( p<0.05), although segment motion was purely vertical. These data disprove the main tenet of most models of pursuit: that it is a system that seeks to minimise retinal image motion through negative feedback. Rather, the main drive must be a visual signal which has already integrated spatiotemporal retinal information into an object-motion signal.

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Visual Coherence Affects Smooth Pursuit

Perception ◽

10.1068/v96l0202 ◽

1996 ◽

Vol 25 (1_suppl) ◽

pp. 10-10

Author(s):

B R Beutter ◽

J Lorenceau ◽

L S Stone

Keyword(s):

Object Motion ◽

Image Motion ◽

High Luminance ◽

Perceptual Effect ◽

Low Contrast ◽

Line Segments ◽

Motion Signal ◽

Contrast Condition ◽

Retinal Image Motion ◽

Moving Line

For four subjects (one naive), we measured pursuit of a line-figure diamond moving along an elliptical path behind an invisible X-shaped aperture under two conditions. The diamond's corners were occluded and only four moving line segments were visible over the background (38 cd m−2). At low segment luminance (44 cd m−2), the percept is largely a coherently moving diamond. At high luminance (108 cd m−2), the percept is largely four independently moving segments. Along with this perceptual effect, there were parallel changes in pursuit. In the low-contrast condition, pursuit was more related to object motion. A \chi2 analysis showed ( p>0.05) that for 98% of trials subjects were more likely tracking the object than the segments, for 29% of trials one could not reject the hypothesis that subjects were tracking the object and not the segments, and for 100% of trials one could reject the hypothesis that subjects were tracking the segments and not the object. Conversely, in the high-contrast condition, pursuit appeared more related to segment motion. For 66% of trials subjects were more likely tracking the segments than the object; for 94% of trials one could reject the hypothesis that subjects were tracking the object and not the segments; and for 13% of trials one could not reject the hypothesis that subjects were tracking the segments and not the object. These results suggest that pursuit is driven by the same object-motion signal as perception, rather than by simple retinal image motion.

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Glossiness Perception Enhanced by Retinal-Image Motion from Object-Motion and Self-Motion

i-Perception ◽

10.1068/ic366 ◽

2011 ◽

Vol 2 (4) ◽

pp. 366-366 ◽

Cited By ~ 2

Author(s):

Keisuke Araki ◽

Masaya Kato ◽

Takehiro Nagai ◽

Kowa Koida ◽

Shigeki Nakauchi ◽

...

Keyword(s):

Retinal Image ◽

Object Motion ◽

Image Motion ◽

Retinal Image Motion ◽

Self Motion

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A simple approach to ignoring irrelevant variables by population decoding based on multisensory neurons

Journal of Neurophysiology ◽

10.1152/jn.00005.2016 ◽

2016 ◽

Vol 116 (3) ◽

pp. 1449-1467 ◽

Cited By ~ 18

Author(s):

HyungGoo R. Kim ◽

Xaq Pitkow ◽

Dora E. Angelaki ◽

Gregory C. DeAngelis

Keyword(s):

Intrinsic Noise ◽

Object Motion ◽

Image Motion ◽

Cue Integration ◽

Learning Mechanisms ◽

Optimal Linear ◽

Retinal Image Motion ◽

Heading Estimation ◽

Task Irrelevant ◽

Self Motion

Sensory input reflects events that occur in the environment, but multiple events may be confounded in sensory signals. For example, under many natural viewing conditions, retinal image motion reflects some combination of self-motion and movement of objects in the world. To estimate one stimulus event and ignore others, the brain can perform marginalization operations, but the neural bases of these operations are poorly understood. Using computational modeling, we examine how multisensory signals may be processed to estimate the direction of self-motion (i.e., heading) and to marginalize out effects of object motion. Multisensory neurons represent heading based on both visual and vestibular inputs and come in two basic types: “congruent” and “opposite” cells. Congruent cells have matched heading tuning for visual and vestibular cues and have been linked to perceptual benefits of cue integration during heading discrimination. Opposite cells have mismatched visual and vestibular heading preferences and are ill-suited for cue integration. We show that decoding a mixed population of congruent and opposite cells substantially reduces errors in heading estimation caused by object motion. In addition, we present a general formulation of an optimal linear decoding scheme that approximates marginalization and can be implemented biologically by simple reinforcement learning mechanisms. We also show that neural response correlations induced by task-irrelevant variables may greatly exceed intrinsic noise correlations. Overall, our findings suggest a general computational strategy by which neurons with mismatched tuning for two different sensory cues may be decoded to perform marginalization operations that dissociate possible causes of sensory inputs.

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Motion Aftereffects and Retinal Motion

Perception ◽

10.1068/p180649 ◽

1989 ◽

Vol 18 (5) ◽

pp. 649-655 ◽

Cited By ~ 7

Author(s):

Arien Mack ◽

James Hill ◽

Steven Kahn

Keyword(s):

Alternative Explanation ◽

Image Motion ◽

Motion Signal ◽

Retinal Motion ◽

Tracking Condition ◽

Pattern Motion ◽

Retinal Image Motion ◽

Motion Aftereffects ◽

Direction Opposite ◽

Random Dot Pattern

Two experiments are described in which it was investigated whether the adaptation on which motion aftereffects (MAEs) are based is a response to retinal image motion alone or to the motion signal derived from the process which combines the image motion signal with information about eye movement (corollary discharge). In both experiments observers either fixated a stationary point or tracked a vertically moving point while a pattern (in experiment 1, a grating; in experiment 2, a random-dot pattern) drifted horizontally across the field. In the tracking condition the adapting retinal motion was oblique. In the fixation condition it was horizontal. In every case in both conditions the MAE was horizontal, in the direction opposite to that of pattern motion. These results are consistent with the hypothesis that the adaptation is a response to the motion signal derived from the comparison of eye and image motion rather than to retinal motion per se. An alternative explanation is discussed.

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Effects of Background Stimulation upon Eye-Movement Information

Perceptual and Motor Skills ◽

10.2466/pms.1996.82.2.627 ◽

1996 ◽

Vol 82 (2) ◽

pp. 627-635 ◽

Cited By ~ 3

Author(s):

Shinji Nakamura

Keyword(s):

Eye Movement ◽

Optic Flow ◽

Object Motion ◽

Image Motion ◽

High Contrast ◽

Striped Pattern ◽

Background Stimulus ◽

Background Stimulation ◽

Spatial Frequencies ◽

Retinal Image Motion

To investigate the effects of background stimulation upon eye-movement information (EMI), the perceived deceleration of the target motion during pursuit eye movement (Aubert-Fleishl paradox) was analyzed. In the experiment, a striped pattern was used as a background stimulus with various brightness contrasts and spatial frequencies for serially manipulating the attributions of the background stimulus. Analysis showed that the retinal-image motion of the background stimulus (optic flow) affected eye-movement information and that the effects of optic flow became stronger when high contrast and low spatial frequency stripes were presented as the background stimulus. In conclusion, optic flow is one source of eye-movement information in determining real object motion, and the effectiveness of optic flow depends on the attributes of the background stimulus.

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Effects of retinal-image motion of specular highlights induced by object motion and manual control on glossiness perception.

Journal of Vision ◽

10.1167/13.9.204 ◽

2013 ◽

Vol 13 (9) ◽

pp. 204-204 ◽

Cited By ~ 1

Author(s):

T. Uehara ◽

Y. Tani ◽

T. Nagai ◽

K. Koida ◽

S. Nakauchi ◽

...

Keyword(s):

Retinal Image ◽

Object Motion ◽

Image Motion ◽

Manual Control ◽

Retinal Image Motion ◽

Specular Highlights

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Surface Discontinuity is Critical in a Moving Observer's Perception of Objects’ Depth Order and Relative Motion from Retinal Image Motion

Perception ◽

10.1068/p271153 ◽

1998 ◽

Vol 27 (10) ◽

pp. 1153-1176 ◽

Cited By ~ 4

Author(s):

Michiteru Kitazaki ◽

Shinsuke Shimojo

Keyword(s):

Visual System ◽

Relative Motion ◽

Retinal Image ◽

Object Motion ◽

Image Motion ◽

Depth Order ◽

Velocity Discontinuity ◽

Retinal Image Motion ◽

Surface Discontinuity ◽

Self Motion

The visual system perceptually decomposes retinal image motion into three basic components that are ecologically significant for the human observer: object depth, object motion, and self motion. Using this conceptual framework, we explored the relationship between them by examining perception of objects’ depth order and relative motion during self motion. We found that the visual system obeyed what we call the parallax-sign constraint, but in different ways depending on whether the retinal image motion contained velocity discontinuity or not. When velocity discontinuity existed (eg in dynamic occlusion, transparent motion), the subject perceptually interpreted image motion as relative motion between surfaces with stable depth order. When velocity discontinuity did not exist, he/she perceived depth-order reversal but no relative motion. The results suggest that the existence of surface discontinuity or of multiple surfaces indexed by velocity discontinuity inhibits the reversal of global depth order.

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