Fig. 1.

Simulation of primary DBS surgery (targeting the Vim nucleus; green electrodes and electric fields) and revision surgery (targeting the subthalamic DRT; yellow electrodes and electric fields). a Three-dimensional rendition as viewed from posterior. Electric fields in both situations show clear and bilateral involvements of the DRT. Left revision surgery shows proximity to the medial lemniscus (ML). Yellow arrows indicate missing depiction of the DRT’s crossing, which is a downside of the deterministic tracking algorithm. b Thalamic level (roughly at level of MCP) shows coverage of DRT fibers (yellow) by the electric fields (green) of initial DBS surgery. c Subthalamically the electric fields after revision surgery (yellow) are smaller but still cover the entire DRT. Legend: DN = dentate nucleus, DRT = dentate-rubro-thalamic tract, ML = medial lemniscus, RN = red nucleus, SNr = substantia nigra, STN = subthalamic nucleus