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Une première vague de potentiels d'action, une première vague idée de la scène visuelle - rôle de l'asynchronie dans le traitement rapide de l'information visuelle.

Abstract : The speed with which the human visual system can analyze a complex visual scene constitutes a fundamental biological constraint for theories of neuronal information processing. Psychophysics and electrophysiology measures during a rapid visual categorization task show that the visual system can activate a high-level representation of the visual input in only 150 ms. This holds for natural as well as artifactual target categories. Cerebral activity can be recorded as early as 75 ms post-stimulus, but mostly reflects the physical properties of the stimulus, whereas activity after 150 ms is clearly related to the subject's behavior. From a theoretical viewpoint, what neural mechanisms could underly such a capacity?
The hierarchical organization of the primate visual system, as well as the electrical conduction delays, suggest that information transmission should be essentially feed-forward, and that only one spike for each neuron can encode information between 2 successive processing stages. This rules out spike firing rate codes, classically used in vision connectionnist models. I suggest instead that visual information can be encoded by the relative spike firing times over a population of neurons, the most salient information always being represented by the first spikes. The temporal structure of the first wave of spikes generated by the retina in response to a visual stimulation can carry information explicitely. This spike wave, propagating through the system, is regenerated at each processing stage, and its temporal structure can be modified by (i) the cortical neurons' selectivities, (ii) lateral interactions and (iii) top-down attentional influences from central cortical areas. The concept of temporal asynchrony inside a single spike wave allows to consider in a unique theoretical framework the fundamental and complementary notions of neural information coding and representation, visual saliency and spatial attention.
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https://tel.archives-ouvertes.fr/tel-00078702
Contributor : Catherine Marlot <>
Submitted on : Wednesday, June 7, 2006 - 10:55:44 AM
Last modification on : Friday, January 10, 2020 - 9:08:47 PM
Long-term archiving on: : Tuesday, September 18, 2012 - 2:35:10 PM

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Rufin Vanrullen. Une première vague de potentiels d'action, une première vague idée de la scène visuelle - rôle de l'asynchronie dans le traitement rapide de l'information visuelle.. Neurosciences [q-bio.NC]. Université Paul Sabatier - Toulouse III, 2000. Français. ⟨tel-00078702⟩

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