al–Oxford A. Patients underwent DBS surgery on the STN aspreviously described.10In Cases 2, 7, and 8 (see Table 1), thelocations of the electrodes were confirmed with immediate post-operative fast spin-echo T2-weighted magnetic resonance imag-ing (MRI) with a Leksell frame still in situ. In the remainingcases, locations were confirmed with immediate postoperativecomputed tomography (CT) with a Leksell or CRW frame(Integra Radionics, Burlington, MA) still in situ. CT scans werethen fused with preoperative T2-weighted MRI.11Electrodeextension cables were externalized through the scalp to enablerecordings prior to connection to a subcutaneous DBS pace-maker, implanted in a second operative procedure up to 7 dayslater. The permanent quadripolar macroelectrode used wasmodel 3389 (Medtronic Neurologic Division, Minneapolis,MN), featuring 4 platinum–iridium cylindrical surfaces. Itscontacts are numbered 0, 1, 2, and 3, with 0 being the mostcaudal and contact 3 being the most cranial.We recorded bipolar LFP activity from contacts 0–2 and1–3 of the electrodes in the STN after overnight withdrawalof antiparkinsonian medication between operations for elec-trode placement and pacemaker implantation. LFPs wereband-pass  filtered  between  3  and  37Hz  and  amplified(39,100) using a 3-stage common mode rejection amplifier.The system