Broca's area and the ventral premotor cortex in language: functional differentiation and specificity.

The idea is put forward that Broca's area (BA 44/45) and the left ventral premotor cortex (BA 6) together with the frontal operculum support different functions during language processing. While BA 44/45 is seen to be increasingly activated whenever the internal re-construction of a hierarchical structure from a sequential input is necessary, BA 6 is involved in the processing of local structural dependencies. This functional differentiation is discussed in the context of the neurocytoarchitectonical differentiation between agranular structure characterizing BA 6 and a dysgranular cortical structure characterizing BA 44/45. This differentiation is exemplified in the domain of language, but is possibly applicable to non-language domains.