Linguistic theory and neuroimaging evidence: an fMRI study of Broca's area in lexical semantics.

There has been a long debate on the functional characterization of left inferior frontal cortex, including proposals regarding syntactic and lexico-semantic involvement. We studied nine right-handed adults, using functional magnetic resonance imaging (fMRI) during performance on a semantic decision task in which subjects had to determine whether noun-verb pairs were semantically associated. In comparison with a visuoperceptual control task, activation clusters were seen in left inferior frontal and middle temporal regions, as well as the bilateral superior frontal gyrus. In agreement with previous studies, our findings suggest that Broca's area is involved in semantic processing. Findings of lexico-semantic as well as syntactic processing in the inferior frontal lobe may be accounted for in terms of working memory demands.