Nomi propri, categorie semantiche, parole astratte e concrete: correlati neurali in pazienti con glioma cerebrale

Several studies have suggested different neural circuits for different categories of stimuli. The present studies explore in patients submitted to surgical removal of a glioma, the role of cortical and subcortical structures involved in processing abstract and concrete words. In the first study living and non-living objects were investigated. Direct electrical cortical stimulation was used to map naming of living/non-living entities during surgical removal, then subcortical connections for specific categories of objects were investigated. Two different pathways were identified, one for living and one for non-living things. These results constitute a neurophysiological evidence for the critical role of subcortical pathways as part of the neural circuits that represent lexical-conceptual knowledge of different categories of objects. The second study focused on proper names retrieval and its relationship with the uncinate fasciculus. Forty-four patients with a brain tumor in the left frontal or temporal lobe were examined. In 18 of them surgical removal included the uncinate fasciculus. Patients were assessed before surgery, three-seven days after surgery and three months after surgery. This procedure allowed understanding whether there was any difference due to the lesion of uncinate fasciculus. Patients with removal of the uncinate fasciculus were impaired in naming famous faces and objects. In the third study processing of abstract and concrete nouns was investigated. Fifty-six patients with a brain tumor in the left and right frontal or temporal lobe were examined by means of a semantic similarity judgment. The results suggest that the anterior temporal and the left fronto-insular regions are involved in processing abstract words.