title: Thematic role assignment in the posterior parietal cortex: A TMS study.
abstract: Verbs denote relations between entities acting a role in an event. Thematic roles are essential to the correct use of verbs and involve both semantic and syntactic aspects. We used repetitive Transcranial Magnetic Stimulation (rTMS) to study the involvement of three different left parietal sites in the understanding of thematic roles. In a sentence-to-picture matching task, twelve participants were asked to judge whether or not a given picture matched with a written sentence. Pictures represented simple reversible actions, and sentences were in the active or passive diathesis. Whereas both active and passive sentences require the correct encoding of thematic roles, passives also imply thematic reanalysis, as the canonical order of thematic roles is systematically reversed. The experiment was divided in three sessions. In each session a different parietal site (anterior, middle, posterior) was stimulated at 5 Hz in an event-related fashion, time-locked to the presentation of visual stimuli. Results showed increased accuracy for passive sentences following posterior parietal stimulation. The effect appeared to be (a) TMS-related, as no effect was observed in a control, no-TMS experiment with eighteen new participants; (b) independent from semantic processes involved in word-picture association, as no TMS-related effects were observed in a picture-word matching task. We interpret the results as showing that the posterior parietal site is specifically involved in the assignment of thematic roles, in particular when the correct interpretation of a sentence requires reanalysis of temporarily encoded thematic roles, as in passive reversible sentences.
authors: Dipartimento di Psicologia e Scienze Cognitive, Università di Trento, Trento, Italy. Electronic address: chiara.finocchiaro@unitn.it.
authors: Chiara
authors: C
authors: Finocchiaro
authors: S.C.A. Associati, Roma, Italy.
authors: Rita
authors: R
authors: Capasso
authors: Center for Mind/Brain Sciences (CIMeC), Trento, Italy.
authors: Luigi
authors: L
authors: Cattaneo
authors: Center for Mind/Brain Sciences (CIMeC), Trento, Italy.
authors: Arianna
authors: A
authors: Zuanazzi
authors: Dipartimento di Psicologia e Scienze Cognitive, Università di Trento, Trento, Italy; Center for Mind/Brain Sciences (CIMeC), Trento, Italy.
authors: Gabriele
authors: G
authors: Miceli
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D007802:Language; D007807:Language Tests; D008279:Magnetic Resonance Imaging; D008297:Male; D009483:Neuropsychological Tests; D010296:Parietal Lobe / Q000502:physiology*; D010775:Photic Stimulation; D011930:Reaction Time; D050781:Transcranial Magnetic Stimulation / Q000379:methods; D014796:Visual Perception / Q000502:physiology*; D055815:Young Adult
keywords: Brain mapping; Natural language processing; Posterior parietal lobe; Reanalysis; Thematic role assignment; Transcranial magnetic stimulation