Converging metabolic and functional networks for tremor expression and deep brain stimulation-mediated control

Area of Science:

• Neuroscience
• Neurology
• Medical Imaging

Background:

• Movement disorders involve symptom-specific brain network dysfunction.
• Targeted neuromodulation, like deep brain stimulation (DBS), can influence these networks.
• Connectome analyses map brain networks using lesion and stimulation data.

Purpose of the Study:

• To investigate stimulation-induced and tremor-related metabolic changes in essential tremor patients undergoing thalamic DBS.
• To link metabolic changes to normative connectome data and predict clinical improvement.
• To explore the overlap between circuits involved in tremor generation and therapeutic response.

Main Methods:

• Used [18F]-fluorodeoxyglucose (FDG)-PET in 14 essential tremor patients during thalamic DBS.
• Analyzed within-subject regional metabolic changes related to stimulation and tremor.
• Combined metabolic data with normative functional connectivity connectome results.

Main Results:

• Thalamic DBS increased metabolism in motor cortical and cerebellar regions, identified as key hubs in the tremor treatment network.
• Individual alignment with this network predicted clinical tremor improvement (R² = 0.593, p = 0.007).
• Regions showing increased metabolism with stimulation also exhibited higher metabolism during tremor expression.

Conclusions:

• Findings support indirect connectome-based models by linking them to brain glucose metabolism.
• Deep brain stimulation for essential tremor appears to relieve symptoms by modulating the same circuits underlying symptom expression.
• Individualized network connectivity may predict DBS treatment efficacy for movement disorders.