The neural bases of autobiographical memory: how personal recollections interact with emotion and influence semantic memory

The main aim of the present thesis has to help improving our understanding of neural mechanisms underlying autobiographical memory (AbM), particularly how personal recollections interact with emotion and influence semantic memory Our first study investigated the neural correlates of spontaneous re-living of emotion during recollection of personal event cued with personally known faces. Our findings suggested that the use of highly self-relevant stimuli and the collection of data with no previous refreshment of the memory trace (i) influenced the right lateralisation of the activation in the medial temporal lobe (MTL), and (ii) involved increased activity in the cortical midline structures and subcortical circuits, known to sustain the self-generated emotion, even though no emotion was explicitly acknowledged. In our second study, the aforementioned nonverbal experiment was compared with a verbal one involving pre-scanning testing in order to clarify whether the lateralisation issue of the general network sustaining AbM retrieval. Our finding of a predominantly left-lateralized cerebral network in both experiments suggested that left-sided pattern of brain activations is associated with AbM retrieval per se in healthy subjects. The third experimental work of the present thesis focused on the influence of autobiographical significance on the semantic memory cerebral network. Our results provided functional neuroimaging evidence that autobiographically significant semantic knowledge relies on a pattern of brain activations different from that underlying ‘purely’ semantic knowledge, with the core difference being located at the MTL. The last study investigated the neuronanatomical representations of both autobiographical and semantic remote memory in two patients presenting with left temporal lobe epilepsy. (i) We provided functional neuroimaging evidence of the dissociation within remote memory (autobiographical vs semantic). (ii) Importantly, we documented dissociation within semantic memory for famous people according to the nature of material. Our last experimental work confirms the importance of combining neuropsychological and neuroimaging methods in appropriate patients in order to better understand human memory functions