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56
The dynamics of bi-stable alternation in ambiguous motion displays: a fresh look at plaids
, 2003
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Temporal dynamics in Bistable Perception
- Journal of Vision. No
, 2005
"... Bistable perception is fundamentally a dynamic process: Our perceptual experience continuously alternates when an ambiguous or rivalrous stimulus is observed. Here we present a method to analyze instantaneous measures of dominance and transition between percepts. The analysis extracts three time-var ..."
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Cited by 23 (2 self)
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Bistable perception is fundamentally a dynamic process: Our perceptual experience continuously alternates when an ambiguous or rivalrous stimulus is observed. Here we present a method to analyze instantaneous measures of dominance and transition between percepts. The analysis extracts three time-varying probabilities. First, the transient preference represents the probability of perceiving one interpretation at one instant. Second, the reversal probability is the probability that the current percept will change at the next evaluation. Finally, the survival probabilities are the probability that at one instant the current percept will not switch to the alternative interpretation. We derive the relationships between these probabilities and offer a test of independence between consecutive percepts. We also introduce a simple technique to sample the observer’s perception at regular intervals. The analyzing method is illustrated with the example of binocular rivalry. We demonstrate Levelt’s second proposition with the survival probability measure and show that the consecutive rivalrous percepts are not independent. Keywords: bistability, perceptual dynamics, ambiguous perception, binocular rivalry, Levelt’s second proposition
Unraveling adaptation and mutual inhibition in perceptual rivalry
"... 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 repr ..."
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Cited by 21 (0 self)
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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.
Searching for the switch: neural bases for perceptual rivalry alternations
- Brain Mind
, 2001
"... Abstract. A midbrain neural basis for the perceptual oscillations of binocular rivalry is suggested on the basis of fMRI studies of rivalry and inferences from the properties of rivalry that cannot be explained from the known properties of primary visual cortical (V1) neurons. The rivalry switch is ..."
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Cited by 16 (3 self)
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Abstract. A midbrain neural basis for the perceptual oscillations of binocular rivalry is suggested on the basis of fMRI studies of rivalry and inferences from the properties of rivalry that cannot be explained from the known properties of primary visual cortical (V1) neurons. The rivalry switch is proposed to activate homologous areas of each cerebral hemisphere alternately, by means of a bistable oscillator circuit that straddles the midline of the ventral tegmentum. This bistable oscillator operates at the same slow rate that is characteristic of perceptual rivalry alternations. Whilst attempting to divert the present preoccupation with cortical mechanisms for rivalry, the new proposal integrates many cortical areas, in keeping with recent evidence that binocular rivalry involves widespread areas of the hemispheres. By linking rivalry to interhemispheric switching mechanisms in this way, the new proposal for the switch makes the prediction that binocular rivalry will be subject to high level influences such as mood and motivation. These predictions are being fulfilled, with rivalry playing an increasing role in the diagnosis and understanding of mood disorders, schizophrenia and other psychiatric conditions. Key words: binocular rivalry, interhemispheric switch, midbrain oscillator, neural basis
Neural field model of binocular rivalry waves
- J. Comput. Neurosci. PMID
, 2011
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N (2003): The dynamics of bi-stable alternation in ambiguous motion displays: A fresh look at plaids. Vision Res 43:531–548
"... Prolonged observations of moving plaids lead to bi-stable alternations between coherency and transparency. However, most studies of plaids used brief presentations and a 2AFC between the two interpretations, thus overlooking the dynamical aspect of plaid per-ception. In other domains, most notably b ..."
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Cited by 12 (1 self)
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Prolonged observations of moving plaids lead to bi-stable alternations between coherency and transparency. However, most studies of plaids used brief presentations and a 2AFC between the two interpretations, thus overlooking the dynamical aspect of plaid per-ception. In other domains, most notably binocular rivalry, it was shown that the dynamics of the bi-stable alternations reveal important insights about the underlying mechanisms. Here we develop methods to study the dynamics of plaid perception. Observers continually indicated their percept (coherency or transparency) during presentations that lasted 1–5 min. Two measures of the relative strength of the coherency percept were derived from those data: C=C þ T , the relative time spent seeing coherency, and RTtransp, the response time to report transparency. Those measures are independent of each other yet tightly correlated, and both show systematic relations to manipulations of plaid parameters. Furthermore, the two measures are sensitive to manipulations in wide parametric regimes, in-cluding ranges where brief-presentation methods suffer from ‘‘ceiling’ ’ and ‘‘floor’ ’ effects. We conclude that studying the dynamics of bi-stability in plaids can provide new and unsuspected findings about motion integration and segmentation.
Periodic perturbations producing phase-locked fluctuations in visual perception
- Journal of Vision
, 2009
"... This paper describes a novel psychophysical and analytical technique, called periodic perturbation, for creating and characterizing perceptual waves associated with transitions in visibility of a stimulus during binocular rivalry and during binocular fusion. Observers tracked rivalry within a small, ..."
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Cited by 11 (3 self)
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This paper describes a novel psychophysical and analytical technique, called periodic perturbation, for creating and characterizing perceptual waves associated with transitions in visibility of a stimulus during binocular rivalry and during binocular fusion. Observers tracked rivalry within a small, central region of spatially extended rival targets while small, brief increments in contrast (“triggers”) were presented repetitively in antiphase within different regions of the two rival targets. Appropriately timed triggers produced entrainment of rivalry alternations within the central region, with the optimal timing dependent on an observer’s native alternation rate. The latency between trigger and state switch increased with the distance between the location of the trigger and the central region being monitored, providing evidence for traveling waves of dominance. Traveling waves produced by periodic perturbation exhibited the same characteristics as those generated using a less efficient, more demanding discrete trial technique. We used periodic perturbation to reveal a novel relation between the dynamics associated with the spontaneous perceptual alternations and the speed of traveling waves across observers. In addition, we found evidence for traveling waves even when the events triggering them were initiated within regions of the visual field where binocular vision was stable, in the absence of binocular rivalry, implying that perceptual organization generally depends on spatio-temporal context.
Bi-stable depth ordering of superimposed moving gratings
"... Ambiguous stimuli with two distinct interpretations give rise to perceptual alternations between them. During prolonged viewing of transparently moving gratings, observers report periods of perceiving one grating in front of the other, alternating with periods of the reverse depth ordering. We measu ..."
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Cited by 4 (1 self)
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Ambiguous stimuli with two distinct interpretations give rise to perceptual alternations between them. During prolonged viewing of transparently moving gratings, observers report periods of perceiving one grating in front of the other, alternating with periods of the reverse depth ordering. We measured the percepts ’ dominance times to study the effect of depth cues (wavelength, duty cycle, and speed) on the perceived depth ordering. The grating with shorter wavelength, lower duty cycle, or higher speed was perceived as being behind the other for a fraction of time larger than one half. The fraction of time spent perceiving each grating as behind changed gradually as a function of the parameters. The fraction of dominance depended on the ratio between the gratings ’ wavelengths, not on their absolute sizes. The wavelength ratio had a stronger effect on perceived depth than that of duty cycle or speed and could override stereoscopic disparity cues. Similar results were obtained with superimposed moving surfaces of random dots. The findings are interpreted in terms of their relation to statistical properties of natural surfaces and provide evidence that the fraction of dominance of each percept represents the likelihood that it corresponds to the true interpretation of the underlying scene.
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, 2012
"... doi: 10.3389/fphys.2012.00054 The splicing factor SRSF1 as a marker for endothelial senescence ..."
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Cited by 4 (0 self)
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doi: 10.3389/fphys.2012.00054 The splicing factor SRSF1 as a marker for endothelial senescence
