Psychophysical evidence for area V2 involvement in the reduction of subjective contour tilt aftereffects by binocular rivalry

Zwan, Rick van der; Wenderoth, Peter

doi:10.1017/s0952523800003114

Cited by 34 publications

(17 citation statements)

References 32 publications

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“…It has been suggested that the neural events underlying rivalry suppression precede those underlying the synthesis of subjective contours. For example, rivalry suppression reduced the magnitude of the tilt aftereffect when the adapting and test patterns are subjective contours [35], and suppression is unaffected by a moving subjective contour whereas the formation of a subjective contour is impaired as indexed by the contour’s failure to enhance probe detection [36]. It is possible that under interocular suppression, some aspect of the perceptual grouping process occurred which made a difference in suppression time, but may not lead to a full representation of the illusory contour.…”

Section: Discussionmentioning

confidence: 99%

Perceptual Grouping without Awareness: Superiority of Kanizsa Triangle in Breaking Interocular Suppression

Wang

Weng

2012

PLoS ONE

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Much information could be processed unconsciously. However, there is no direct evidence on whether perceptual grouping could occur without awareness. To answer this question, we investigated whether a Kanizsa triangle (an example of perceptual grouping) is processed differently from stimuli with the same local components but are ungrouped or weakly grouped. Specifically, using a suppression time paradigm we tested whether a Kanizsa triangle would emerge from interocular continuous flash suppression sooner than control stimuli. Results show a significant advantage of the Kanizsa triangle: the Kanizsa triangle emerged from suppression noise significantly faster than the control stimulus with the local Pacmen randomly rotated (t(9) = −2.78, p = 0.02); and also faster than the control stimulus with all Pacmen rotated 180° (t(11) = −3.20, p<0.01). Additional results demonstrated that the advantage of the grouped Kanizsa triangle could not be accounted for by the faster detection speed at the conscious level for the Kanizsa figures on a dynamic noise background. Our results indicate that certain properties supporting perceptual grouping could be processed in the absence of awareness.

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Section: Discussionmentioning

confidence: 99%

Perceptual Grouping without Awareness: Superiority of Kanizsa Triangle in Breaking Interocular Suppression

Wang

Weng

2012

PLoS ONE

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“…Along this cortical network, the visual system implements a sequence of actions that include the processing of local features, surface boundary contours, and surface/object representation. For example, a number of psychophysical studies have demonstrated that image properties that are largely processed in the extrastriate cortices can significantly affect binocular rivalry (e.g., Alais & Blake, 1999; Kovacs et al, 1996; Ooi & He, 2003, 2006; Paffen et al, 2005; Shimojo & Nakayama, 1990; Sobel & Blake, 2002; Su et al, 2009; van Bogaert et al, 2008; van der Zwan & Wenderoth, 1994; Xu et al, 2010). Binocular rivalry is thus the collective outcomes of these sequential processes that lead to binocular surface representation.…”

Section: Discussionmentioning

confidence: 99%

The magnitude and dynamics of interocular suppression affected by monocular boundary contour and conflicting local features

Ooi

2010

Vision Research

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A monocular boundary contour (MBC) rivalry stimulus has two half-images, a homogeneous grating and the same homogeneous grating with an additional disc region. The outline/frame of the MBC disc is created by relative phase-shift, or orientation difference. We found the increment contrast threshold and reaction time to detect a monocular Gabor probe elevated on the homogeneous half-image pedestal. The interocular suppression begins as early as 80 msec upon stimulus onset. Moreover, the suppression magnitude is larger when the MBC disc is defined by orientation difference rather than phase-shift, revealing the suppression caused by competing local features in addition to MBC.

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“…() demonstrated that the magnitude of the tilt aftereffect using line‐end‐induced subjective contours was largest at an adaptation angle of 10–20°, consistent with investigations using real contour stimuli (Clifford et al ., ). The ability to elicit the tilt aftereffect illusion to line‐end‐induced subjective contours is suggested to arise from orientation‐selective neurons in V2 (Baizer et al ., ), functioning in the same manner as those that respond to real contours in area V1 (Vanderzwan and Wenderoth, ). Thus, it is reasonable to predict that if serotonin provides the same function in orientation‐selective neurons in area V2 as in V1, then residual effects of ecstasy use, given their potential for reductions in serotonergic function, should result in a similar increase in the magnitude of the tilt aftereffect when tested with subjective contour stimuli as has been observed for real contours.…”

Section: Possible Confounding Effects Of Other Drugsmentioning

confidence: 99%

Residual effects of ecstasy (3,4‐methylenedioxymethamphetamine) on low level visual processes

Murray

Bruno

Brown

2012

Human Psychopharmacology

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'Ecstasy' (3,4-methylenedioxymethamphetamine) induces impaired functioning in the serotonergic system, including the occipital lobe. This study employed the 'tilt aftereffect' paradigm to operationalise the function of orientation-selective neurons among ecstasy consumers and controls as a means of investigating the role of reduced serotonin on visual orientation processing. The magnitude of the tilt aftereffect reflects the extent of lateral inhibition between orientation-selective neurons and is elicited to both 'real' contours, processed in visual cortex area V1, and illusory contours, processed in V2. The magnitude of tilt aftereffect to both contour types was examined among 19 ecstasy users (6 ecstasy only; 13 ecstasy-plus-cannabis users) and 23 matched controls (9 cannabis-only users; 14 drug-naive). Ecstasy users had a significantly greater tilt magnitude than non-users for real contours (Hedge's g = 0.63) but not for illusory contours (g = 0.20). These findings provide support for literature suggesting that residual effects of ecstasy (and reduced serotonin) impairs lateral inhibition between orientation-selective neurons in V1, which however suggests that ecstasy may not substantially affect this process in V2. Multiple studies have now demonstrated ecstasy-related deficits on basic visual functions, including orientation and motion processing. Such low-level effects may contribute to the impact of ecstasy use on neuropsychological tests of visuospatial function.

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Psychophysical evidence for area V2 involvement in the reduction of subjective contour tilt aftereffects by binocular rivalry

Cited by 34 publications

References 32 publications

Perceptual Grouping without Awareness: Superiority of Kanizsa Triangle in Breaking Interocular Suppression

Perceptual Grouping without Awareness: Superiority of Kanizsa Triangle in Breaking Interocular Suppression

The magnitude and dynamics of interocular suppression affected by monocular boundary contour and conflicting local features

Residual effects of ecstasy (3,4‐methylenedioxymethamphetamine) on low level visual processes

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