What is the anatomical and functional organization of the brain areas involved in representing linguistic structures ? The main brain areas activated during sentence processing are now known : these are the left inferior frontal convolution and a string of regions located deep in the superior temporal sulcus. Activation is also observed in other dorsal (premotor cortex) mesial (precuneus) and subcortical (left putamen) regions. These regions are coactivated and show strong functional connectivity during sentence processing. The temporal and inferior frontal regions are anatomically interconnected by the arcuate bundle (particularly developed and asymmetrical in humans compared to other primate species), the uncinate bundle, and the extreme capsule.
Various experiments have attempted to clarify whether a subset of this network is particularly interested in tree-like syntactic structures. Their results point to the posterior part of the superior temporal sulcus (pSTS) and the triangular part of the inferior frontal gyrus (IFGtri). Syntactic ambiguity, for example, specifically increases activity in these regions. The same applies when the task requires manipulation of syntactic trees to determine " who does what to whom " (e.g. : " the truck overtaking the car is red " to what is red ? ).
