Unraveling adaptation and mutual inhibition in rivalry

Functional Neurobiology and Helmholtz Institute, Utrecht University, Utrecht, The Netherlands.
Journal of Vision (Impact Factor: 2.39). 02/2006; 6(4):304-10. DOI: 10.1167/6.4.1
Source: PubMed


When the visual system is confronted with incompatible images in the same part of the visual field, the conscious percept switches back and forth between the rivaling stimuli. Such spontaneous flips provide important clues to the neuronal basis for visual awareness. The general idea is that two representations compete for dominance in a process of mutual inhibition, in which adaptation shifts the balance to and fro. The inherent nonlinear nature of the rivalrous flip-flop and its stochastic behavior, however, made it impossible to disentangle inhibition and adaptation. Here we report a general method to measure the time course, and asymmetries, of mechanisms involved in perceptual rivalry. Supported by model simulations, we show the dynamics of opponent interactions between mutual inhibition and adaptation. The findings not only provide new insight into the mechanism underlying rivalry but also offer new opportunities to study and compare a wide range of bistable processes in the brain and their relation to visual awareness.

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Available from: Martin Lankheet,
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    • "At the broadest level, therefore , Levelt's propositions and related findings are consistent with the idea that this set of assumptions has merit, as is also suggested by other evidence (e.g. Alais et al., 2010; Blake, Sobel, & Gilroy, 2003; Kang & Blake, 2010; Lankheet, 2006; Pastukhov & Braun, 2011; Suzuki & Grabowecky, 2002; van Loon et al., 2013). "
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    ABSTRACT: It has been fifty years since Levelt's monograph On Binocular Rivalry (1965) was published, but its four propositions that describe the relation between stimulus strength and the phenomenology of binocular rivalry remain a benchmark for theorists and experimentalists even today. In this review, we will revisit the original conception of the four propositions and the scientific landscape in which this happened. We will also provide a brief update concerning distributions of dominance durations, another aspect of Levelt's monograph that has maintained a prominent presence in the field. In a critical evaluation of Levelt's propositions against current knowledge of binocular rivalry we will then demonstrate that the original propositions are not completely compatible with what is known today, but that they can, in a straightforward way, be modified to encapsulate the progress that has been made over the past fifty years. The resulting modified, propositions are shown to apply to a broad range of bistable perceptual phenomena, not just binocular rivalry, and they allow important inferences about the underlying neural systems. We argue that these inferences reflect canonical neural properties that play a role in visual perception in general, and we discuss ways in which future research can build on the work reviewed here to attain a better understanding of these properties. Copyright © 2015. Published by Elsevier Ltd.
    Vision Research 03/2015; 109(Pt A). DOI:10.1016/j.visres.2015.02.019 · 1.82 Impact Factor
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    • "Although several studies have challenged the role of adaptation [but see e.g. 6,7,8], there is substantial evidence that adaptation plays a significant role in binocular rivalry alternations [9], [10], [11], [12], [13], [14]. Evidence for the involvement of reciprocal inhibition originates from Levelt’s [15] influential study on binocular rivalry dynamics which characterized how alternations between the two percepts are affected by the strengths of the stimuli in the two eyes. "
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    ABSTRACT: 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.
    PLoS ONE 08/2013; 8(8):e71931. DOI:10.1371/journal.pone.0071931 · 3.23 Impact Factor
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    • "Therefore, noise has also been incorporated in computational models of adaptation-inhibition based perceptual decisions, in order to account for the irregular character of perceptual alternations (e.g., Wilson, 2003, 2007; Noest et al., 2007; Shpiro et al., 2009). It has been suggested that it exerts a crucial, perhaps dominating role (Brascamp et al., 2006; Lankheet, 2006). Stochastic resonance is a noisy-driven process with the virtue of allowing for deterministic (adaptational) influences to take place as well, as in the case of rivalry (van Ee, 2009). "
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    ABSTRACT: When different stimuli are presented dichoptically, perception alternates between the two in a stochastic manner. After a long-lasting and rigorous debate, there is growing consensus that this phenomenon, known as binocular rivalry (BR), is the result of a dynamic competition occurring at multiple levels of the visual hierarchy. The role of low- and high-level adaptation mechanisms in controlling these perceptual alternations has been a key issue in the rivalry literature. Both types of adaptation are dispersed throughout the visual system and have an equally influential, or even causal, role in determining perception. Such an explanation of BR is also in accordance with the relationship between the latter and attention. However, an overall explanation of this intriguing perceptual phenomenon needs to also include noise as an equally fundamental process involved in the stochastic resonance of perceptual bistability.
    Frontiers in Human Neuroscience 03/2012; 6:35. DOI:10.3389/fnhum.2012.00035 · 3.63 Impact Factor
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