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Jeremy Gadette

Jérémy Gardette


jeremy.gardette@univ-smb.fr

LPNC
Vision & Emotion Team
PhD : A representational approach to hippocampal functions and pathologies

Research overview

The hippocampus and other medial temporal lobe (MTL) structures are associated with memory in main neuropsychological models, whereas more posterior areas are usually associated with perception. Temporal areas are altered in various pathologies such as Alzheimer’s disease, strokes, or temporal-lobe epilepsy. Memory deficits have thus been demonstrated in these clinical populations, using tasks stemming from traditional neuropsychological models. Specifically, the hippocampus would be responsible of recollection, being the process of retrieving a memory in its context with many details. Conversely, the process of familiarity, or feeling that a stimulus has been encountered before (without remembering when or where) would rely on the perirhinal cortex, and be independent of the hippocampus (see Aggleton & Brown, 1999 ; 2006). In other words, classical models of temporal areas propose a functional organisation depending on cognitive processes. This last decade, there has been growing evidence questioning these traditional models, and supporting an alternative account, leading to the representational view of occipito-temporal areas (see the work of T. Bussey & L. Saksida). Representational models stipulate that the ventral-visual stream, ending in the MTL, is functionally organised depending on the nature and complexity of the representations processed, and not on cognitive processes (more details and a literature review in Cowell, Sadil, and Barense, 2019). Hence, this view is essentially cross-processual, suggesting that MTL as well as posterior areas are involved both in perception and memory. According to this account, the hippocampus’ specialisation in cognition would be to process highly-complex representations, being spatial scenes, whatever the cognitive process engaged. This is supported by studies showing either deficits amongst hippocampal patients or hippocampal activations controls in visual discrimination and matching, short-term memory, imagination, future thinking, and recognition tasks, when scenes are involved. Our work aims to test certain predictions of representational models in fMRI and lesion studies, in order to specify the features responsible for the involvement of the hippocampus in perception and memory, and to better characterise the deficits found in hippocampal pathologies.

Teaching
1st year : Experimental methodology (USMB)
2nd year : Psychometry (USMB)
2nd year : Questionnaire building (USMB)
2nd year : Cognition & Memory (USMB)
Master’s : Memory and its deficits (Neuropsychology Master’s, USMB)