Ref [[Motor Thalamic Anatomy]] ### Treatment for refractory pure ET - VIM DBS - Guiot target: - ~11 mm lateral from the third ventricle wall (14 mm from midline if the 3rd ventricle is 6 mm wide) (x) - 25% of AC-PC length anterior to the PC (y) - At the AC-PC depth (z) - After electrophysiological mapping and balancing tremor reduction with Vc parasthesia, implant lead often ends up in 2-4 mm anterior to the Vim/ Vc (Hassler's) border (y) ^[Gross RE, Krack P, Rodriguez-Oroz MC, Rezai AR, Benabid AL. Electrophysiological mapping for the implantation of deep brain stimulators for Parkinson’s disease and tremor. _Movement Disorders_. 2006;21(S14):S259-S283. doi:[10.1002/mds.20960](https://doi.org/10.1002/mds.20960)], at the lower (z) and mid-lateral (x) part of Vim - Hassler's VIM is VIM measures 4 mm anterioposteriorly, 4 mm mediolaterally, and 6 mm dorsoventrally, thus the lead is between mid Vim to the Vim/ Vop border (y) - While the depth (z) and laterality (x) localize to hand following Hassler's thalamic hommunculus, effect at the Vop/ Vim (Hassler) (~ VLp/ VPL (Jones)) border (y) infuse some doubts into the separating of these two nuclei - ![[Pasted image 20250202194858.png]] ^[https://www.brainkart.com/article/Ventral-Nuclear-Group---Dorsal-Thalamus_14845/] - Approach: double oblique (ant, lat) to avoid the ventricle, though not too lateral to minimize proportion of the proximal lead in the internal capsule