Abstract. The medial temporal lobe (MTL) is a set of interconnected structures located on the medial face of the temporal lobe, among which the hippocampus and perirhinal cortex. Numerous results have challenged the view that these regions constitute a module exclusively dedicated to declarative memory. A different type of models thus emerged, built around the notion of representation. Further, it was proposed to decompose cognitive processes into representations and operations. In this view, the representation is the key factor determining the engagement of a given MTL region in a cognitive process, independently of the operation. Our work aimed to assess the predictions of the RH model, and to investigate how its principles of functional organisation interact with the long axis of the hippocampus.
We first investigated, in two behavioural studies (N=66 and N=76), how the process of recollection can be broken down into a representation and an operation, using a partial-cue image reconstruction paradigm. Our results showed that it is possible to isolate pattern-completion of scenes and objects, but that additional cognitive mechanisms can be confounded depending on task instructions. In a subsequent fMRI study (N=51), we replicated the previous result that the hippocampus is specifically engaged in pattern-completion of scenes compared with objects. In contrast, the perirhinal cortex was more recruited by object than by scene processing. We also extended it to additional operations (i.e., visual-discrimination and familiarity-based memory), thereby supporting the RH view of the MTL: the preferential engagement of the hippocampus and perirhinal cortex in scene and single object representations, respectively, is independent of the operation. Finally, we highlighted a scene-selective region within the hippocampus, in line with previous studies suggesting that the functional specialisation of this region varies both along its longitudinal and transverse axes.
Biosketch. I am a postdoctoral researcher at CRC in Dr Christine Bastin’s team. I studied cognitive and clinical neuroscience in Grenoble; then did my PhD in the LPNC lab in Chambéry, under the supervision of Prof. Pascal Hot. During my PhD, I worked on the functional specialization of medial temporal lobe regions in memory and visual perception. To this end, I conducted behavioral and neuroimaging studies in healthy controls, as well as studies of patients with brain lesions.
Publications related to the talk.
Gardette, J., Cousin, E., Bourgin, J., Torlay, L., Pichat, C., Moreaud, O., & Hot, P. (2022). Hippocampal activity during memory and visual perception : The role of representational content. Cortex. https://doi.org/10.1016/j.cortex.2022.09.004
Gardette, J., Cousin, E., & Hot, P. (2023). The anterior medial hippocampus contributes to both recall and familiarity-based memory for scenes. Neurobiology of Learning and Memory, 206, 107859. https://doi.org/10.1016/j.nlm.2023.107859
Gardette, J., Delhaye, E., Bastin, C., & Hot, P. (2024). Approche représentationnelle de la mémoire : Revue théorique et implications pour l’évaluation neuropsychologique. Revue de neuropsychologie, 16(1), 5‑13.
Gardette, J., Mosca, C., Asien, C., Borg, C., Mazzola, L., Convers, P., Gal, G., Banjac, S., Baciu, M., Durocher, B., Kahane, P., & Hot, P. (2023). Complex visual discrimination is impaired after right, but not left, anterior temporal lobectomy. Hippocampus. https://doi.org/10.1002/hipo.23569