We used Magnetic Resonance-guided Focused Ultrasound to reduce hand tremor in 13 patients with Parkinson’s disease and essential tremor, by lesioning the ventral intermediate nucleus (VIM) of the thalamus. We also investigated the functional reorganization of the brain after the procedure. We observed a 67% reduction in target hand tremor following the procedure. The regions that showed above-average change in functional connectivity are part of the cerebello-thalamo-cortical tremor network, confirming that lesioning the VIM was successful in targeting this network. We also observed some normalization in the functional connectivity of the target hand motor region, congruent with tremor alleviation.