Immediate and Longitudinal Alterations of Functional Networks after Thalamotomy in Essential Tremor.
Thalamotomy at the ventralis intermedius nucleus has been an effective treatment method for essential tremor, but how the brain network changes immediately responding to this deliberate lesion and then reorganizes afterwards are not clear. Taking advantage of a non-cranium-opening MRI-guided focused ultrasound ablation technique, we investigated functional network changes due to a focal lesion. To classify the diverse time courses of those network changes with respect to symptom-related long-lasting treatment effects and symptom-unrelated transient effects, we applied graph-theoretic analyses to longitudinal resting-state functional magnetic resonance imaging data before and 1 day, 7 days, and 3 months after thalamotomy with essential tremor. We found reduced average connections among the motor-related areas, reduced connectivity between substantia nigra and external globus pallidum and reduced total connection in the thalamus after thalamotomy, which are all associated with clinical rating scales. The average connectivity among whole brain regions and inter-hemispheric network asymmetry show symptom-unrelated transient increases, indicating temporary reconfiguration of the whole brain network. In summary, thalamotomy regulates interactions over the motor network via symptom-related connectivity changes but accompanies transient, symptom-unrelated diaschisis in the global brain network. This study suggests the significance of longitudinal network analysis, combined with minimal-invasive treatment techniques, in understanding time-dependent diaschisis in the brain network due to a focal lesion.
BK21 PLUS Project for Medical Science, Severance Hospital, Yonsei University College of Medicine , Seoul , South Korea.
Changwon
C
Jang
BK21 PLUS Project for Medical Science, Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea; Department of Nuclear Medicine, Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea; Department of Radiology, Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea; Department of Psychiatry, Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea; Department of Cognitive Science, Yonsei University, Seoul, South Korea.
Hae-Jeong
HJ
Park
Department of Neurosurgery, Yonsei University College of Medicine , Seoul , South Korea.
Won Seok
WS
Chang
BK21 PLUS Project for Medical Science, Severance Hospital, Yonsei University College of Medicine , Seoul , South Korea.
Chongwon
C
Pae
Department of Neurosurgery, Yonsei University College of Medicine , Seoul , South Korea.
Jin Woo
JW
Chang
brain network; connectivity; diaschisis; essential tremor; thalamotomy