Fig. 1.

a–c Deep brain stimulation (DBS) electrode positions (postoperative computed tomography superimposed onto preoperative T2-weighted MRI scans): a axial view at the level of the inter-commissural plane; b coronal view; c parasagittal view. Blue arrowheads in a and c indicate previous implantation site of a DBS electrode (removed). A second electrode (from a previous operation, removed) was located intraventricularly, its tract site is not discernible. d, e Results from diffusion tensor imaging (DTI) fibre-tracking analysis combined with individual electric field simulation studies: d unsuccessful previous treatment with two DBS electrodes; e successful stimulation attempt over VCP and PAG DBS electrodes now reaching the medial (blue MPNS) and lateral (pink ML) systems (acg anterior cingulate gyrus [BA24], ATR anterior thalamic radiation, IC/STP internal capsule/superior thalamic peduncle, MPNS midline polysynaptic nociceptive system, VCP nucleus ventralis caudalis posterior, PVG/PAG periventricular grey/periaqueductal grey, prcg precentral gyrus, pcg postcentral gyrus, sfg superior frontal gyrus, TL/ML trigeminal lemniscus/medial lemniscus)