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Poster De Conférence Année : 2022

Multistability: Physiological 'signature' of perceptual changes in ambiguous vision

Multi-stabilité : « signature » neurophysiologique des changements perceptuels dans la vision ambiguë

Résumé

Multi-stable stimuli: Certain visual stimuli that are either static or dynamic, such as Rubin's vase/face and Wallach's (1935) moving sinusoidal gratings (also known as 'moving plaid'), induce mutually exclusive perception of shape or motion, known as 'percepts', which oscillate over time. These stimuli are called multi-stable stimuli, where a single stationary signal can generate different interpretations called percepts. A bistable stimulus, such as Rubin's vase/face, generates two mutually exclusive static percepts (percept 'faces' or percept 'vase'). The dynamic plaid is tri-stable under certain conditions and can therefore generate three mutually exclusive dynamic percepts. Paradigm: Current explanatory models for multistability are based on adaptation and learning mechanisms as well as on the importance of noise (in particular the oculomotor noise) in the perceptual and decision-making system. Oculomotor noise is often considered as a harmful component, but it can also be understood as a facilitating element of the perceptual system. Our eye is always in motion: even during eye fixation (the phase of eye stability), our eye makes micro-movements. It will be necessary here to relate these micromovements to perceptual tilts in the face of multi-stable stimuli. However, the access to perceptual states is a real issue: participant's report of their perceptual state through a motor response can alter the perceptual state itself. To overcome this alteration, we will learn to discriminate the perceptual changes over time through brain activity recorded by electroencephalography (EEG). This EEG learning allows us to do without the motor report, and thus to avoid a disturbance of the participant's endogenous activity. Objective: - Characterize a “signature” of endogenous perceptual changes using EEG signals and ocular micromovements (useful for No report paradigm). - Characterize a model of multi-stable perception i) explaining the dynamics of the observed perceptual reversals and ii) able to correctly predict perceptual changes. - Originality compared to the existing literature: we incorporate EEG and ocular micromovements signals as variables in our model. Methods: - Tri-stable (ambiguous) plaid creation and its monostables (non ambiguous) counterparts (small visual differences needed). - Extraction of endogenous “signature”: crossing endogenous/exogenous signal x motor response/no response variables. Estimate the oculometric activity before and after the perceptual reversal intervals previously estimated from the EEG activity. Oculometric activity will be observed by measuring microsaccade rates and directions. EEG activity will be observed in the characteristic frequency bands of the EEG signal. - Test prediction of the model on testing datasets (collected datas split into learning and testing datatsets).
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Dates et versions

hal-04001364 , version 1 (03-03-2023)

Identifiants

  • HAL Id : hal-04001364 , version 1

Citer

Juliette Lenouvel, Ronald Phlypo, Alan Chauvin, Michèle Rombaut. Multistability: Physiological 'signature' of perceptual changes in ambiguous vision. Journée des doctorant.e.s et post-doctorant.e.s du pôle PSD (Pôle Sciences des Données), Mar 2022, Grenoble, France. ⟨hal-04001364⟩
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