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Interactions audiovisuelles dans le cortex auditif chez l'homme : approches électrophysiologique et comportementale.

Abstract : Audiovisual interactions taking place during the perception of audiovisual events were explored in two mainly auditory phenomena: speech perception and representation in auditory sensory memory (ASM), by means of behavioural and electrophysiological measures.
Concerning speech perception, we have shown that seeing lip mouvements can speed up auditory speech processing in a phonological discrimination task in normal hearing conditions. This behavioral facilitation was associated with both an activation of the (mainly secondary) auditory cortices by lip movements, as shown in intracranial ERPs in epileptic patients, and a decrease of auditory activity within 50-200 ms after sound onset, as shown both in intracranial ERPs in patients and surface ERPs in normal subjects. We have also shown that a behavioural facilitation can be observed even if the visual speech cues carry temporal, but no phonetic, information, but only in noisy environments.
Concerning ASM, we have shown that the detection of a rare audiovisual event delivered in a sequence of standard events is faster than that of either visual or auditory events. This facilitation was associated with interactions of the auditory and visual detection processes, based on the existence of auditory and visual sensory memory traces, as indexed by auditory and visual MMNs of the scalp ERPs. We also showed that the representation of an audiovisual event in ASM, as indexed by the auditory MMN, differs from that of its purely auditory component, but only if the unimodal components of this event are regularly associated. However, we failed to show that a representation of such a regularity can trigger an MMN to its violation.
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https://tel.archives-ouvertes.fr/tel-00161510
Contributor : Julien Besle <>
Submitted on : Tuesday, July 10, 2007 - 6:53:44 PM
Last modification on : Wednesday, November 20, 2019 - 3:18:55 AM
Long-term archiving on: : Thursday, April 8, 2010 - 10:54:57 PM

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  • HAL Id : tel-00161510, version 1

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Julien Besle. Interactions audiovisuelles dans le cortex auditif chez l'homme : approches électrophysiologique et comportementale.. Neurosciences [q-bio.NC]. Université Lumière - Lyon II, 2007. Français. ⟨tel-00161510⟩

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