Functional segregation in the left premotor cortex in language processing: evidence from fMRI.

Functional segregation has been revealed in the premotor cortex (PMC) and is related to motor and sensorimotor behaviors. Few data is available concerning the existence of similar segregation in the PMC during language processing. Here we correlated the roles of subregions of the left PMC in picture naming and articulation using functional magnetic resonance imaging (fMRI) and covert and overt picture naming in healthy volunteers. The results showed that the left dorsal PMC was extensively activated by covert picture naming, suggesting its recruitment in the naming network. The left ventral PMC was activated after comparison of overt vs. covert naming, suggesting its participation in articulation. These results may indicate that there is dorsal and ventral segregation of the left PMC during language processing.