title: Neural basis of understanding communicative actions: Changes associated with knowing the actor's intention and the meanings of the actions.
abstract: People can communicate by using hand actions, e.g., signs. Understanding communicative actions requires that the observer knows that the actor has an intention to communicate and the meanings of the actions. Here, we investigated how this prior knowledge affects processing of observed actions. We used functional MRI to determine changes in action processing when non-signers were told that the observed actions are communicative (i.e., signs) and learned the meanings of half of the actions. Processing of hand actions activated the left and right inferior frontal gyrus (IFG, BA 44 and 45) when the communicative intention of the actor was known, even when the meanings of the actions remained unknown. These regions were not active when the observers did not know about the communicative nature of the hand actions. These findings suggest that the left and right IFG play a role in understanding the intention of the actor, but do not process visuospatial features of the communicative actions. Knowing the meanings of the hand actions further enhanced activity in the anterior part of the IFG (BA 45), the inferior parietal lobule and posterior inferior and middle temporal gyri in the left hemisphere. These left-hemisphere language regions could provide a link between meanings and observed actions. In sum, the findings provide evidence for the segregation of the networks involved in the neural processing of visuospatial features of communicative hand actions and those involved in understanding the actor's intention and the meanings of the actions.
authors.affiliation: Department of Experimental Psychology, University of Oxford, South Parks Road, Oxford OX1 3UD, UK; Centre for Functional Magnetic Resonance Imaging of the Brain (FMRIB), University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, UK. Electronic address: riikka.mottonen@psy.ox.ac.uk.
authors.forename: Riikka
authors.initials: R
authors.lastname: Möttönen
authors.affiliation: Department of Experimental Psychology, University of Oxford, South Parks Road, Oxford OX1 3UD, UK.
authors.forename: Harry
authors.initials: H
authors.lastname: Farmer
authors.affiliation: Department of Experimental Psychology, University of Oxford, South Parks Road, Oxford OX1 3UD, UK; Centre for Functional Magnetic Resonance Imaging of the Brain (FMRIB), University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, UK.
authors.forename: Kate E
authors.initials: KE
authors.lastname: Watkins
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001921:Brain / Q000098:blood supply / Q000502:physiology*; D001931:Brain Mapping; D003142:Communication; D032882:Comprehension / Q000502:physiology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D033182:Intention; D008279:Magnetic Resonance Imaging; D008297:Male; D009068:Movement / Q000502:physiology*; D010100:Oxygen / Q000097:blood; D010775:Photic Stimulation; D011795:Surveys and Questionnaires
chemical_list: D010100:Oxygen
keywords: Action observation; Communication; Inferior frontal cortex; Inferior parietal lobule; Mirror neuron system; Mirror neurons; Sign language