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Functional MRI Shows Altered Deactivation and a Corresponding Decrease in Functional Connectivity of the Default Mode
Y M Maniar1, K K Peck2,3, M Jenabi1
1From the Department of Radiology (Y.M.M., K.K.P., M.J., M.G., A.I.H.), Memorial Sloan Kettering Cancer Center, New York, New York.
Background And Purpose:
The default mode network normally decreases in activity during externally directed tasks. Although default mode network connectivity is disrupted in numerous brain pathologies, default mode network deactivation has not been studied in patients with brain tumors. We investigated default mode network deactivation with language task-based fMRI by measuring the anticorrelation of a critical default mode network node, the posterior cingulate cortex, in patients with gliomas and controls; furthermore, we examined default mode network functional connectivity in these patients with task-based and resting-state fMRI.
Materials And Methods:
In 10 healthy controls and 30 patients with gliomas, the posterior cingulate cortex was identified on task-based fMRI and was used as an ROI to create connectivity maps from task-based and resting-state fMRI data. We compared the average correlation in each default mode network region between patients and controls for each correlation map and stratified patients by tumor location, hemisphere, and grade.
Results:
Patients with gliomas (P = .001) and, in particular, patients with tumors near the posterior default mode network (P < .001) showed less posterior cingulate cortex anticorrelation in task-based fMRI than controls. Patients with both left- and right-hemisphere tumors, as well as those with grade IV tumors, showed significantly lower posterior cingulate cortex anticorrelation than controls (P = .02, .03, and <.001, respectively). Functional connectivity in each default mode network region was not significantly different between task-based and resting-state maps.
Conclusions:
Task-based fMRI showed impaired deactivation of the default mode network in patients with gliomas. The functional connectivity of the default mode network in both task-based and resting-state fMRI in patients with gliomas using the posterior cingulate cortex identified in task-based fMRI as an ROI for seed-based correlation analysis has strong overlap.
Insights
Brain tumor patients with gliomas show impaired default mode network deactivation during tasks. This default mode network dysfunction was observed using functional MRI, highlighting differences compared to healthy controls.
Area of Science:
- Neuroimaging
- Cognitive Neuroscience
- Oncology
Background:
- The default mode network (DMN) typically decreases activity during external tasks.
- DMN connectivity disruptions are common in brain pathologies.
- DMN deactivation has not been previously studied in brain tumor patients.
Purpose of the Study:
- Investigate DMN deactivation in glioma patients using language task-based fMRI.
- Measure posterior cingulate cortex (PCC) anticorrelation as a key DMN node.
- Examine DMN functional connectivity in patients using task-based and resting-state fMRI.
Main Methods:
- Used task-based fMRI to identify PCC in 10 controls and 30 glioma patients.
- Created connectivity maps from task-based and resting-state fMRI data using PCC as a region of interest (ROI).
- Compared DMN region correlations between patients and controls, stratified by tumor characteristics.
Main Results:
- Glioma patients exhibited significantly less PCC anticorrelation during tasks compared to controls (P = .001).
- Tumor proximity to the DMN, tumor location (left/right hemisphere), and higher tumor grade (IV) correlated with reduced PCC anticorrelation.
- Task-based and resting-state fMRI showed no significant differences in DMN functional connectivity.
Conclusions:
- Task-based fMRI reveals impaired DMN deactivation in patients with gliomas.
- DMN functional connectivity demonstrates strong overlap between task-based and resting-state fMRI in glioma patients.
- PCC-seeded analysis effectively characterizes DMN alterations in brain tumor patients.
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