Reorganization of Functional Connectivity of the Language Network in Patients with Brain Gliomas

BACKGROUND AND PURPOSE: fcMRI measures spontaneous and synchronous fluctuations of BOLD
signal between spatially remote brain regions. The present study investigated potential LN fcMRI
modifications induced by left hemisphere brain gliomas.
MATERIALS AND METHODS: We retrospectively evaluated fcMRI in 39 right-handed patients with a left
hemisphere brain glioma and 13 healthy controls. Patients and controls performed a verb-generation
task to identify individual BOLD activity in the left IFG (Broca area); the active region was used as seed
to create whole-brain background connectivity maps and to identify the LN (including bilateral regions
of the IFG, STS, and TPJ) following regression of task-evoked activity. We assessed differences
between patients and controls in the pattern of functional connectivity of the LN, as well as potential
effects of tumor position, histopathology, and volume.
RESULTS: Global fcMRI of the LN was significantly reduced in patients with tumor compared with
controls. Specifically, fcMRI was significantly reduced within seed regions of the affected hemisphere
(left intrahemispheric fcMRI) and between the TPJ of the 2 hemispheres. In patients, the left TPJ node
showed the greatest decrease of functional connectivity within the LN.
CONCLUSIONS: The presence of a brain tumor in the left hemisphere significantly reduced the degree
of fcMRI between language-related brain regions. The pattern of fcMRI was influenced by tumor
position but was not restricted to the area immediately surrounding the tumor because the connectivity
between remote and contralateral areas was also affected.