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Étude du système visuel ventral dans l’épilepsie du lobe temporal à partir d’une nouvelle approche en électrophysiologie

Abstract : The ventral visual stream extends from the occipital to the anterior temporal regions and is specialized in recognizing objects and people through vision. Numerous studies in functional magnetic resonance imaging have focused on the cerebral basis of visual recognition. However, this technique is susceptible to magnetic artefacts in anterior temporal regions and it has led to an underestimation of the role of these regions within the ventral visual stream. The aim of this thesis is to better understand the mechanisms of visual recognition within the ventral occipito-temporal cortex and, more specifically, to clarify the contribution of posterior and anterior temporal structures in the visual recognition of a stimulus and its association with semantic representations. For this purpose, we used a multimodal approach combining neuropsychology, fast periodic visual stimulation (FPVS), and scalp and intracerebral EEG (SEEG) recordings in neurotypical and epileptic participants. We report five empirical studies in which we demonstrate that (1) patients with anterior temporal epilepsy (i.e., the most frequent type of focal epilepsy that undergo intracerebral EEG recordings) show typical performance in individual face discrimination, (2) electrical stimulation of the right anterior fusiform gyrus can lead to a transient deficit that is specific to face recognition, even when no naming is required, (3) familiar face discrimination processes involve a large network of bilateral ventral structures including the anterior and medial temporal regions, (4) some structures of the left ventral anterior temporal lobe are involved in the integration of a familiar face and its name into a unified representation, and (5) the bilateral ventral anterior temporal regions are involved in representing semantic knowledge associated with written words. Overall, this work shows that (1) the visual recognition network follows a progressive hierarchization along the postero-anterior axis of the ventral visual stream, with a graded transition between perceptual representations and increasingly abstract semantic representations, and (2) the regions involved in visual recognition are strongly lateralized in the ventral posterior regions and become bilateral in the ventral anterior temporal regions.
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https://hal.univ-lorraine.fr/tel-03021093
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Submitted on : Tuesday, November 24, 2020 - 10:51:09 AM
Last modification on : Wednesday, November 25, 2020 - 3:27:12 AM

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  • HAL Id : tel-03021093, version 1

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Angélique Volfart. Étude du système visuel ventral dans l’épilepsie du lobe temporal à partir d’une nouvelle approche en électrophysiologie. Sciences cognitives. Université de Lorraine, 2020. Français. ⟨NNT : 2020LORR0119⟩. ⟨tel-03021093⟩

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