My general interest is in the field of Cognitive Neuroscience of memory and more precisely in the characterization of the similarities, differences, and interactions between the semantic and episodic systems. The goal of my Ph.D. research consisted in trying to understand whether we process the meaning of words similarly when they are repeated or presented for the first time in an experiment. A number of studies have shown that repetition can disrupt the processing of meaning, resulting in a reduction or a suppression of semantic effects. I have investigated whether effects such as semantic priming, concreteness or effects of semantic category would be maintained or suppressed for highly repeated words. Results indicate that semantic processing and its neural bases (as indexed by the N400 ERP) are similar in repeated and non-repeated conditions, as long as participants are explicitly invited to process meaning. This maintenance of semantic processing with multiple repetitions was demonstrated both in prime-target designs and in designs with single-word trials. In contrast, in tasks in which access to the meaning of words is not necessary, such as in lexical decision tasks, repetition resulted in a suppression of semantic effects. Current projects consist in extending this research to the knowledge we have about ourselves, sometimes referred to as personal semantic memory. This entails knowing about one’s past personal events as well as about one’s personality traits. These aspects of autobiographical memory have been much less studied than episodic memory processes. The goal of this work is thus to understand if personal semantic memory is a homogeneous and distinct declarative memory system or if this type of knowledge emerges from interactions between the semantic, episodic and self-reference systems. The neural bases of these different types of memory will be compared using ERPs and fMRI.