  Functional magnetic resonance imaging (fMRI) is widely used in clinical
applications to highlight brain areas involved in specific cognitive processes.
Brain impairments, such as tumors, suppress the fMRI activation of the
anatomical areas they invade and, thus, brain-damaged functional networks
present missing links/areas of activation. The identification of the missing
circuitry components is of crucial importance to estimate the damage extent.
The study of functional networks associated to clinical tasks but performed by
healthy individuals becomes, therefore, of paramount concern. These `healthy'
networks can, indeed, be used as control networks for clinical studies. In this
work we investigate the functional architecture of 20 healthy individuals
performing a language task designed for clinical purposes. We unveil a common
architecture persistent across all subjects under study, which involves Broca's
area, Wernicke's area, the Premotor area, and the pre-Supplementary motor area.
We study the connectivity weight of this circuitry by using the k-core
centrality measure and we find that three of these areas belong to the most
robust structure of the functional language network for the specific task under
study. Our results provide useful insight for clinical applications on
primarily important functional connections which, thus, should be preserved
through brain surgery.
