Single session of rTMS enhances brain metastability and intrinsic ignition

Background Emerging evidence support the view that brain stimulation might improve essential tremor (ET) by altering brain dynamics and facilitating brain plasticity. Yet, we are still missing a mechanistic explanation of the whole brain dynamics underlying these plasticity defining changes. Method In this study, we explored the effect of low-frequency repetitive transcranial magnetic stimulation (rTMS) over primary motor cortex (M1) on dynamic functional connectivity (DFC) in patients with ET. Resting state fMRI (RsfMRI) was acquired before and after a single session of rTMS in 30 patients with ET and compared with RsfMRI of 20 age, gender and education matched healthy controls (HCs). We have measured the effect of brain stimulation using network topological re-organization through whole brain integration and segregation, brain stability and capacity of neural propagation through metastability and intrinsic ignition. Results Patients with ET had altered DFC measures compared to controls. After a single session rTMS, the connectivity measures approached normality and patients with ET revealed significantly higher integration, lower segregation with higher metastability and increased intrinsic ignition. Conclusion Brain metastability and intrinsic ignition measures could be valuable tools in appreciating mechanisms of brain stimulation in ET and other neurological diseases.