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Abstract

Most previous neuroimaging studies of sentence processing have associated Broca’s area with syntactic processing; however, the exact nature of the processes subserved by this brain region is yet not
well understood. Although some authors suggest that Brodmann area (BA) 44 of the left inferior frontal
gyrus (i.e., Broca’s area) is relevant for syntactic integration processes, others claim that it is associated
with working memory mechanisms relevant for language processing. To dissociate these two possible
functions, the present study investigated hemodynamic responses elicited while participants processed
German indirect wh-questions. Activation increases were observed in left BA 44 together with superior
temporal areas and right hemispheric homologues for sentences with noncanonical word order, in which
a verb argument was dislocated from its canonical position over a relatively long distance. In these
sentences, syntactic working memory load was assumed to be greatest. In contrast, no activation increase
was elicited by object–initial as opposed to subject–initial sentences that did not differ with respect to
working memory costs but with respect to syntactic integration costs. These data strongly suggest that
Broca’s area plays a critical role in syntactic working memory during online sentence comprehension.