Fronto-parietal dorsal and ventral pathways in the context of different linguistic manipulations

This study investigates structural connectivity between left fronto-parietal brain regions that were identified in a previous fMRI study which used different linguistic manipulation tasks. Diffusion-weighted images were acquired from 20 volunteers. Structural connectivity between brain regions from the fMRI study was computed using probabilistic fiber tracking. For suprasegmental manipulation, left inferior parietal lobule (IPL) and left inferior frontal gyrus (IFG), pars opercularis, were connected by a dorsal pathway via the arcuate fascicle and superior longitudinal fascicle III. For segmental manipulation, left IPL and IFG, pars triangularis, were connected by a ventral pathway via the middle longitudinal fascicle and the extreme capsule. We conclude that the dorsal pathway provides a route for mapping from phonological memory in IPL to the inferior frontal articulatory network while the ventral pathway could facilitate the modulation of phonological units based on lexical-semantic aspects, mediate the complexity of auditory objects and the unification of actor-event schemata.