Influence of contrast and coherence on the temporal dynamics of binocular motion rivalry.

Levelt's four propositions (L1-L4), which characterize the relation between changes in "stimulus strength" in the two eyes and percept alternations, are considered benchmark for binocular rivalry models. It was recently demonstrated that adaptation mutual-inhibition models of binocula...

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Main Authors: Artem Platonov, Jeroen Goossens
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2013-01-01
Series:PLoS ONE
Online Access:http://europepmc.org/articles/PMC3743782?pdf=render
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author Artem Platonov
Jeroen Goossens
author_facet Artem Platonov
Jeroen Goossens
author_sort Artem Platonov
collection DOAJ
description Levelt's four propositions (L1-L4), which characterize the relation between changes in "stimulus strength" in the two eyes and percept alternations, are considered benchmark for binocular rivalry models. It was recently demonstrated that adaptation mutual-inhibition models of binocular rivalry capture L4 only in a limited range of input strengths, predicting an increase rather than a decrease in dominance durations with increasing stimulus strength for weak stimuli. This observation challenges the validity of those models, but possibly L4 itself is invalid. So far, L1-L4 have been tested mainly by varying the contrast of static stimuli, but since binocular rivalry breaks down at low contrasts, it has been difficult to study L4. To circumvent this problem, and to test if the recent revision of L2 has more general validity, we studied changes in binocular rivalry evoked by manipulating coherence of oppositely-moving random-dot stimuli in the two eyes, and compared them against the effects of stimulus contrast. Thirteen human observers participated. Both contrast and coherence manipulations in one eye produced robust changes in both eyes; dominance durations of the eye receiving the stronger stimulus increased while those of the other eye decreased, albeit less steeply. This is inconsistent with L2 but supports its revision. When coherence was augmented in both eyes simultaneously, dominance durations first increased at low coherence, and then decreased for further increases in coherence. The same held true for the alternation periods. The initial increase in dominance durations was absent in the contrast experiments, but with coherence manipulations, rivalry could be tested at much lower stimulus strengths. Thus, we found that L4, like L2, is only valid in a limited range of stimulus strengths. Outside that range, the opposite is true. Apparent discrepancies between contrast and coherence experiments could be fully reconciled with adaptation mutual-inhibition models using a simple input transfer-function.
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spelling doaj.art-5944a9d7d79b42679227249a12915a012022-12-21T23:53:22ZengPublic Library of Science (PLoS)PLoS ONE1932-62032013-01-0188e7193110.1371/journal.pone.0071931Influence of contrast and coherence on the temporal dynamics of binocular motion rivalry.Artem PlatonovJeroen GoossensLevelt's four propositions (L1-L4), which characterize the relation between changes in "stimulus strength" in the two eyes and percept alternations, are considered benchmark for binocular rivalry models. It was recently demonstrated that adaptation mutual-inhibition models of binocular rivalry capture L4 only in a limited range of input strengths, predicting an increase rather than a decrease in dominance durations with increasing stimulus strength for weak stimuli. This observation challenges the validity of those models, but possibly L4 itself is invalid. So far, L1-L4 have been tested mainly by varying the contrast of static stimuli, but since binocular rivalry breaks down at low contrasts, it has been difficult to study L4. To circumvent this problem, and to test if the recent revision of L2 has more general validity, we studied changes in binocular rivalry evoked by manipulating coherence of oppositely-moving random-dot stimuli in the two eyes, and compared them against the effects of stimulus contrast. Thirteen human observers participated. Both contrast and coherence manipulations in one eye produced robust changes in both eyes; dominance durations of the eye receiving the stronger stimulus increased while those of the other eye decreased, albeit less steeply. This is inconsistent with L2 but supports its revision. When coherence was augmented in both eyes simultaneously, dominance durations first increased at low coherence, and then decreased for further increases in coherence. The same held true for the alternation periods. The initial increase in dominance durations was absent in the contrast experiments, but with coherence manipulations, rivalry could be tested at much lower stimulus strengths. Thus, we found that L4, like L2, is only valid in a limited range of stimulus strengths. Outside that range, the opposite is true. Apparent discrepancies between contrast and coherence experiments could be fully reconciled with adaptation mutual-inhibition models using a simple input transfer-function.http://europepmc.org/articles/PMC3743782?pdf=render
spellingShingle Artem Platonov
Jeroen Goossens
Influence of contrast and coherence on the temporal dynamics of binocular motion rivalry.
PLoS ONE
title Influence of contrast and coherence on the temporal dynamics of binocular motion rivalry.
title_full Influence of contrast and coherence on the temporal dynamics of binocular motion rivalry.
title_fullStr Influence of contrast and coherence on the temporal dynamics of binocular motion rivalry.
title_full_unstemmed Influence of contrast and coherence on the temporal dynamics of binocular motion rivalry.
title_short Influence of contrast and coherence on the temporal dynamics of binocular motion rivalry.
title_sort influence of contrast and coherence on the temporal dynamics of binocular motion rivalry
url http://europepmc.org/articles/PMC3743782?pdf=render
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AT jeroengoossens influenceofcontrastandcoherenceonthetemporaldynamicsofbinocularmotionrivalry