title: The role of semantics and grammatical class in the neural representation of words.
abstract: On the basis of neuropsychological and functional imaging evidence, meaning and grammatical class (particularly the verb-noun distinction) have been proposed as organizational principles of linguistic knowledge in the brain. However, previous studies investigating verb and noun processing have been confounded by the presence of systematic correlations between word meaning and grammatical class. In this positron emission tomography study, we investigated implicit word processing using stimuli that allowed the effects of semantic and grammatical properties to be examined independently, without grammatical-semantic confounds. We found that left hemisphere cortical activation during single-word processing was modulated by word meaning, but not by grammatical class. Motor word processing produced significant activation in left precentral gyrus, whereas sensory word processing produced significant activation in left inferior temporal and inferior frontal regions. In contrast to previous studies, there were no effects of grammatical class in left inferior frontal gyrus (IFG). Instead, we found semantic-based differences within left IFG: anterior, but not posterior, left IFG regions responded preferentially to sensory words. These findings demonstrate that the neural substrates of implicit word processing are determined by semantic rather than grammatical properties and suggest that word comprehension involves the activation of modality-specific representations linked to word meaning.
authors.affiliation: Department of Psychology, University College London, UK. g.vigliocco@ucl.ac.uk
authors.forename: Gabriella
authors.initials: G
authors.lastname: Vigliocco
authors.forename: Jane
authors.initials: J
authors.lastname: Warren
authors.forename: Simona
authors.initials: S
authors.lastname: Siri
authors.forename: Joanne
authors.initials: J
authors.lastname: Arciuli
authors.forename: Sophie
authors.initials: S
authors.lastname: Scott
authors.forename: Richard
authors.initials: R
authors.lastname: Wise
mesh_terms: D000328:Adult; D001921:Brain / Q000033:anatomy & histology / Q000502:physiology*; D001931:Brain Mapping; D032882:Comprehension / Q000502:physiology*; D005260:Female; D006801:Humans; D007802:Language; D008037:Linguistics; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography; D012660:Semantics; D013067:Speech Perception / Q000502:physiology*; D014705:Verbal Behavior / Q000502:physiology