title: How concepts are encoded in the human brain: A modality independent, category-based cortical organization of semantic knowledge.
abstract: How conceptual knowledge is represented in the human brain remains to be determined. To address the differential role of low-level sensory-based and high-level abstract features in semantic processing, we combined behavioral studies of linguistic production and brain activity measures by functional magnetic resonance imaging in sighted and congenitally blind individuals while they performed a property-generation task with concrete nouns from eight categories, presented through visual and/or auditory modalities. Patterns of neural activity within a large semantic cortical network that comprised parahippocampal, lateral occipital, temporo-parieto-occipital and inferior parietal cortices correlated with linguistic production and were independent both from the modality of stimulus presentation (either visual or auditory) and the (lack of) visual experience. In contrast, selected modality-dependent differences were observed only when the analysis was limited to the individual regions within the semantic cortical network. We conclude that conceptual knowledge in the human brain relies on a distributed, modality-independent cortical representation that integrates the partial category and modality specific information retained at a regional level.
authors.affiliation: Dept. Surgical, Medical, Molecular Pathology and Critical Care, University of Pisa, Pisa 56126, Italy.
authors.forename: Giacomo
authors.initials: G
authors.lastname: Handjaras
authors.affiliation: Dept. Surgical, Medical, Molecular Pathology and Critical Care, University of Pisa, Pisa 56126, Italy.
authors.forename: Emiliano
authors.initials: E
authors.lastname: Ricciardi
authors.affiliation: Dept. Surgical, Medical, Molecular Pathology and Critical Care, University of Pisa, Pisa 56126, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Leo
authors.affiliation: Department of Philology, Literature, and Linguistics, University of Pisa, Pisa 56126, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Lenci
authors.affiliation: Dept. Surgical, Medical, Molecular Pathology and Critical Care, University of Pisa, Pisa 56126, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Cecchetti
authors.affiliation: Neuroradiology Unit, University of Pisa, Pisa 56126, Italy.
authors.forename: Mirco
authors.initials: M
authors.lastname: Cosottini
authors.affiliation: Department of Philology, Literature, and Linguistics, University of Pisa, Pisa 56126, Italy.
authors.forename: Giovanna
authors.initials: G
authors.lastname: Marotta
authors.affiliation: Dept. Surgical, Medical, Molecular Pathology and Critical Care, University of Pisa, Pisa 56126, Italy; Clinical Psychology Branch, Pisa University Hospital, Pisa 56126, Italy; IMT School for Advanced Studies Lucca, Lucca 55100, Italy. Electronic address: pietro.pietrini@imtlucca.it.
authors.forename: Pietro
authors.initials: P
authors.lastname: Pietrini
mesh_terms: D000328:Adult; D001307:Auditory Perception; D001766:Blindness / Q000503:physiopathology*; D002540:Cerebral Cortex / Q000503:physiopathology*; D003198:Computer Simulation; D003210:Concept Formation; D005260:Female; D006801:Humans; D007858:Learning; D008297:Male; D008959:Models, Neurological; D009415:Nerve Net / Q000503:physiopathology; D012660:Semantics; D014706:Verbal Learning
keywords: Blindness; Category-based organization; Multivoxel pattern analysis; Semantic knowledge; Supramodality; fMRI