Neural systems underlying the processing of complex sentences

The functional neuroanatomy of sentence processing is one of the most classical topics of cognitive neuropsychology of speech and language processing. We first outline the cognitive processes involved in the processing of complex sentences with noncanonical and embedded sentence structures, for which cross-linguistic psycholinguistic research has reported increased processing difficulty. We performed an activation likelihood estimate meta-analysis on the activation coordinates from all neurolinguistic imaging studies that report the main effects of either noncanonicity or embedding. The results state that Brodmann area 44 in the left-hemispheric inferior frontal gyrus as well as the left middle and superior temporal gyri are the regions most likely activated during complex sentence processing. From the present review and meta-analysis, we synthesize the common underlying function in complex sentence processing to lie in the establishment of multiple hierarchical dependencies between subjects and objects and their verbs, avoiding their possible interference