Subcortical and Cerebellar Compensation for Motor Control in Medial Frontal Glioblastoma: A Task-Based Connectivity...

Area of Science:

• Neuroscience
• Neurosurgery
• Cognitive Neurology

Background:

• Medial frontal gliomas often infiltrate planning hubs, yet patients retain motor function, suggesting unmapped compensatory networks.
• Standard mapping methods may miss crucial demand-dependent network reorganization in glioma patients.
• Understanding these compensatory mechanisms is vital for surgical preservation of motor function.

Purpose of the Study:

• To identify task-dependent compensatory brain networks in patients with medial frontal gliomas using functional MRI (fMRI).
• To reveal demand-driven network reorganization invisible to standard mapping techniques.
• To determine the functional relevance of these networks for motor control and surgical targets.

Main Methods:

• Task-based functional connectivity analysis using generalized psychophysiological interaction (gPPI) in 25 WHO Grade IV medial frontal glioma patients and 25 controls.
• Visually-paced finger-tapping task (2 Hz) during 3T fMRI.
• Brain-behavior correlations to assess functional relevance of identified networks.

Main Results:

• Canonical sensorimotor and Putamen-Thalamus connectivity were absent in patients.
• Compensation occurred via a Caudate-dominated subcortical network, anterior cerebellar feedback circuits, and enhanced frontoparietal engagement.
• This reorganization correlated with preserved motor accuracy and was observed in 68% of patients, who outperformed those without it.

Conclusions:

• Medial frontal gliomas induce a shift from automatic to cognitively-supervised motor control via a Caudate-cerebellar-frontoparietal axis.
• These compensatory networks are demand-specific and critical surgical targets, often undetectable at rest.
• Individualized preoperative mapping is valuable, as approximately one-third of patients do not engage this reorganization, showing performance deficits.