Accueil > Personnel

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 traditional view in neuropsychology associates the medial temporal lobe (MTL) with memory, whereas more posterior regions are usually associated with perception. Further, the hippocampus would be responsible for the process of recollection, or the rich and contextualised retrieval of a memory. In contrast, familiarity, or the feeling that something (such as a face or a place) has been encountered before, without remembering the context in which it happened, would rely on the perirhinal cortex (PRC). In this view, the MTL would be functionally organised according to distinct mnemonic 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 (Bussey & Saksida, 2007). This view argues that high-level cognitive processes such as recollection and familiarity are too complex to be explicative of neurocognitive functioning, and must rather be considered as the phenomena to explain. The authors thus propose to break down such processes into representations and operations (Cowell, Sadil, and Barense, 2019). The operation involved in recollection is pattern-completion, or the reconstruction of a stimulus from a partial cue. The representation involved in recollection is complex and associative, and traditionally includes a spatial layout, or a scene. When breaking cognitive processes into operations and representations, two hypotheses appear : A representation- and an operation-based accounts. Experimental evidence tends to support the representational account, as it has been demonstrated through fMRI scanning that the engagement of the hippocampus in recollection depends on the representation processed rather than on the reconstructive nature of the retrieval (Ross et al, 2018). However, this demonstration only concerns pattern-completion, while other operations were not investigated. This PhD project aims (1) to replicate the results from Ross and colleagues (not replicated so far) ; (2) to extend such results to other operations such as familiarity-based recognition, and visual discrimination ; (3) to overcome methodological limitations associated with fMRI by (a) applying a Machine-Learning method to fMRI data (Multivariate-Pattern Analysis -MVPA), and (b) applying the protocol to neuropsychological populations such as Temporal-lobe epilepsy and Alzheimer’s disease, in order to test whether the predictions of the representational approach can lead to a better understanding of the cognitive outcomes encountered in these 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)