Cerebral Cortex Advance Access published online on May 8, 2007
Cerebral Cortex, doi:10.1093/cercor/bhm042
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Idiom Comprehension: A Prefrontal Task?
1 Dipartimento di Psicologia, Università di Milano-Bicocca, U6 20126 Milano, Italy, 2 Università Vita-Salute San Raffaele, S. Raffaele Scientific Institute, CERMAC, Istituto Nazionale di Neuroscienze and IBFM-CNR, Milano, Italy
Address correspondence to Costanza Papagno, Dipartimento di Psicologia, Università di Milano-Bicocca, Piazza dell'Ateneo Nuovo 1 Edificio U6, 20126 Milano, Italy. Email: costanza.papagno{at}unimib.it.
We investigated the neural correlates of idiomatic sentence processing using event-related functional magnetic resonance imaging. Twenty-two healthy subjects were presented with 62 literal sentences and 62 idiomatic sentences, each followed by a picture and were required to judge whether the sentence matched the picture or not. A common network of cortical activity was engaged by both conditions, with the nonliteral task eliciting overall greater activation, both in terms of magnitude and spatial extent. The network that was specifically activated by the nonliteral condition involved the left temporal cortex, the left superior medial frontal gyrus (Brodmann area 9), and the left inferior frontal gyrus (IFG). Activations were also present in the right superior and middle temporal gyri and temporal pole and in the right IFG. In contrast, literal sentences selectively activated the left inferior parietal lobule and the right supramarginal gyrus. An analysis of effective connectivity indicated that the medial prefrontal area significantly increased the connection between frontotemporal areas bilaterally during idiomatic processing. Overall, the present findings indicate a crucial role of the prefrontal cortex in idiom comprehension, which could reflect the selection between alternative sentence meanings.
Key Words: anterior prefrontal cortex idiom comprehension RH hypothesis