Substrats neuronaux du traitement sémantique des concepts concrets et abstraits :
apports de la neuropsychologie par l’étude de patients ayant subi une lobectomie temporale gauche ou droite
Research in the field of semantic memory has allowed to document the concreteness effect (advantage for concrete words relative to abstract words), and more recently, the reversal of the concreteness effect (advantage for abstract words relative to concrete words). These effects, observed in healthy subjects and in different clinical neurological populations, have yielded numerous theoretical interpretations, both on cognitive and on neuroanatomical levels. Indeed, this double dissociation between the two kinds of concepts suggests that their processing relies at least partly on distinct mental and neuroanatomical bases. Nevertheless, the origins of those differences remain largely debated and are marked by a notable lack of consensus.  The principal goal of the present thesis is to explore the cerebral substrates underlying the comprehension of concrete and abstract concepts. First, a literature review summarizes current knowledge about the processing of concrete and abstract concepts as well as their neural bases. This article emphasizes in particular the inter-hemispheric differences in the processing of those concepts (Article 1). Secondly, an experimental study of the comprehension of concrete and abstract concepts was conducted with a rare clinical population, patients who have undergone either i) a unilateral resection of the anterior part of the temporal lobe (temporal pole), either ii) a unilateral resection of the hippocampal region (internal temporal structures) (Article 2). The first article highlights the important heterogeneity of the results in the field, and suggests that the observed differences in the processing of concrete and abstract concepts can hardly be explained solely in terms of inter-hemispheric differences. Results of the second article indicate that damage to anterior temporal regions, either left or right, can cause a more pronounced deficit of concrete concepts, as compared to abstract concepts, while damage to internal temporal regions affects the semantic processing of both kinds of concepts in an equivalent way. The theoretical and clinical implications of these results are discussed, and the limits and future research perspectives are also addressed.
Concepts abstraits Semantic memory Concrete concepts Abstract concepts Reversal of the concreteness effect Anterior temporal lobe