Motion direction influences surface segmentation in stereo transparency

Goutcher, Ross

doi:10.1167/16.15.17

Cited by 6 publications

(6 citation statements)

References 49 publications

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“…It has recently become clear that the perception of each observer is shaped by individual biases that can differ greatly from one observer to the next and that can persist over long periods of time (Carter & Cavanagh, 2007;Afraz, Pashkam, & Cavanagh, 2010;Mamassian & Wallace, 2010;Houlsby et al, 2013;Schütz, 2014;Wexler, Duyck, & Mamassian, 2015;Goutcher, 2016;Schütz & Mamassian, 2016;Kosovi-cheva & Whitney, 2017). For example, with my colleagues I have recently shown that the perception of two families of stimuli are shaped by individual biases that are a preferred three-dimensional (3-D) surface orientation for one of the families, and a preferred motion direction for the other family (Wexler et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

Multidimensional internal dynamics underlying the perception of motion

Wexler

2018

Journal of Vision

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When ambiguous visual stimuli are presented continuously, they often lead to oscillations between usually two perceptions. Because of these oscillations, it has been thought that the underlying neural dynamics also arises from a binary or two-state system. Contradicting the binary assumption, it has been shown recently that the perception of some ambiguous stimuli is governed by continuously varying internal states, measured as biases that differ considerably from one observer to the next and that can also evolve over time (Wexler, Duyck, & Mamassian, 2015). Here I study bias patterns in the motion quartet, an ambiguous apparent motion stimulus, as the quartet's orientation is varied. The bias patterns are robustly idiosyncratic, and are even more complex than those that have been described previously. There are two qualitatively different bias types: Some observers prefer a translation axis, while others show preference for a rotation direction. Each type also varies parametrically: the orientation of the preferred axis, and the direction of preferred rotation. There are also clear cases of combination of the two bias types. When measured repeatedly over 9 hr, the bias patterns usually remain stable, but also sometimes evolve both parametrically (e.g., change of preferred axis), as well as across bias type (change from axial to rotational bias). Control experiments revealed that the variety of bias patterns observed across subjects, and their changes over time, are not due to voluntary decisions. Overall, these results exhibit the multidimensional complexity of internal states underlying the perception of even simple stimuli.

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Section: Introductionmentioning

confidence: 99%

Multidimensional internal dynamics underlying the perception of motion

Wexler

2018

Journal of Vision

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“…It has recently become clear that the perception of each observer is shaped by individual biases that can differ greatly from one observer to the next and that can persist over long periods of time (Carter & Cavanagh, 2007;Afraz et al, 2010;Mamassian & Wallace, 2010;Houlsby et al, 2013;Schütz, 2014;Wexler et al, 2015;Schütz & Mamassian, 2016;Goutcher, 2016;Kosovicheva & Whitney, 2017). For example, with my colleagues I have recently shown that the perception of two families of stimuli are shaped by individual biases that are a preferred 3D surface orientation for one of the families, and a preferred motion direction for the other family (Wexler et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

Multidimensional internal dynamics underlying the perception of motion

Wexler¹

2018

Preprint

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When ambiguous visual stimuli are presented continuously, they often lead to oscillations between usually two perceptions. Because of these oscillations, it has been thought that the underlying neural dynamics also arises from a binary or two-state system. Contradicting the binary assumption, it has been shown recently that the perception of some ambiguous stimuli is governed by continuously varying internal states, measured as biases that differ considerably from one observer to the next and that can also evolve over time (Wexler et al., 2015). Here I study bias patterns in the motion quartet, an ambiguous apparent motion stimulus, as the quartet's orientation is varied. The bias patterns are robustly idiosyncratic, and are even more complex than those that have been described previously. There are two qualitatively different bias types: some observers prefer a translation axis, while others show preference for a rotation direction. Each type also varies parametrically: the orientation of the preferred axis, and the direction of preferred rotation. The are also clear cases of combination of the two bias types. When measured repeatedly over 9 hours, the bias patterns usually remain stable, but also sometimes evolve both parametrically (e.g., change of preferred axis), as well as across bias type (change from axial to rotational bias). Control experiments revealed that the variety of bias patterns observed across subjects, and their changes over time, are not due to voluntary decisions. Overall, these results exhibit the multidimensional complexity of internal states underlying the perception of even simple stimuli.

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“…Among other visual features, stereoscopic depth and motion velocity are important cues aiding segmentation. While depth (Wallace and Mamassian 2004) or motion cue alone (Wallace and Mamassian 2003) can lead to segmentation, when combined they further enhance segmentation (Snowden and Rossiter 1999;Goutcher 2016;Kohler et al 2019;Nawrot and Blake 1989;Bradshaw and Rogers 1996;Ban et al 2012). For example, psychophysical studies have shown that it becomes easier to segment overlapping surfaces moving in different directions when they are located at different depths than at the same depth (Hibbard and Bradshaw 1999;Greenwood and Edwards 2006b).…”

Section: Introductionmentioning

confidence: 99%

The role of binocular disparity and attention in the neural representation of multiple moving stimuli in the visual cortex

Chakrala

Xiao

Huang

2023

Preprint

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Natural scenes often contain multiple objects and surfaces in 3-dimensional space. A fundamental process of vision is to segment visual scenes into distinct objects and surfaces. The stereoscopic depth and motion cues are particularly important for segmentation. However, how the primate visual system represents multiple moving stimuli located at different depths is poorly understood. Here we investigated how neurons in the middle temporal (MT) cortex represented two overlapping surfaces located at different horizontal disparities and moved simultaneously in different directions. We recorded the neuronal activities in MT of three male macaque monkeys while two of them performed a discrimination task to report the motion direction of an attended surface of two overlapping stimuli, and the third animal performed a behavioral task with the attention directed away from the receptive fields of MT neurons. We found that neuronal responses to overlapping surfaces showed a robust bias toward the horizontal disparity of one of the two surfaces. For all animals, the disparity bias in response to two surfaces was positively correlated with the disparity preference of the neurons to single surfaces. For two animals, neurons that preferred the near disparities of single surfaces (near neurons) showed a near bias to overlapping stimuli, and neurons that preferred the far disparities (far neurons) showed a far bias. For another animal, both near and far neurons showed a near bias to overlapping stimuli, although near neurons showed a stronger near bias. The disparity bias to overlapping stimuli was delayed relative to the response onset and was more delayed when the angular separation between two motion directions was smaller. Interestingly, for all three animals, both near and far neurons showed an initial near bias in comparison to the average of the responses to individual surfaces. We also found that the effect of attention directed to the disparity of one of two surfaces was object-based rather than feature-based. Although attention can modulate neuronal response to better represent the attended surface, the disparity bias cannot be explained by attention modulation. Our results can be explained by a unified model with a variable pooling size to weigh the response to individual stimulus components and divisive normalization. Our results revealed the encoding rule for multiple horizontal disparities and motion directions of overlapping stimuli. The disparity bias would allow subgroups of neurons to better represent different surfaces of multiple stimuli and therefore provide a population code that aids segmentation. The tendency for MT neurons to better represent the near-surface of overlapping stimuli in one animal and during the early response period in all three animals suggests that the neural representation of multiple stimuli at different depths may be beneficial to figure-ground segregation since figural objects are more likely to be in front of the ground in natural scenes.

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Motion direction influences surface segmentation in stereo transparency

Cited by 6 publications

References 49 publications

Multidimensional internal dynamics underlying the perception of motion

Multidimensional internal dynamics underlying the perception of motion

Multidimensional internal dynamics underlying the perception of motion

The role of binocular disparity and attention in the neural representation of multiple moving stimuli in the visual cortex

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