Functional interactions of the inferior frontal cortex during the processing of words and word-like stimuli

The hypothesis that ventral/anterior left inferior frontal gyrus (LIFG) sub serves semantic processing and dorsal/posterior LIFG subserves phonological processing was tested by determining the pattern of functional connectivit y of these regions with regions in left occipital and temporal cortex durin g the processing of words and word-like stimuli. In accordance with the hyp othesis, we found strong functional connectivity between activity in ventra l LIFG and activity in occipital and temporal cortex only for words, and st rong functional connectivity between activity in dorsal LIFG and activity i n occipital and temporal cortex for words, pseudowords, and letter strings, but not for false font strings. These results demonstrate a task-dependent functional fractionation of the LIFG in terms of its functional links with posterior brain areas.