Effects of GPi-DBS on bradykinesia. Within the GPi cohort, it was noted that in some patients, bradykinetic symptoms worsened under DBS—as stated by previous reports.^28,29 On a local level (top; showing a top and oblique view), the average electric fields of the top six improving and bottom six worsening patients were placed markedly differently, the latter in a more posterolateral location and closer to the GPe border. A paired t-test contrast between connectivity fingerprints of the same patients (bottom) revealed a positive association with left middle and inferior frontal gyrus (bradykinesia improvement) and negative association (worsening) with bilateral cerebellar and occipital regions, as well as the parieto-occipital sulcus (family-wise estimate corrected on cluster level at P < 0.05). Cdt = caudate nucleus; Put = putamen; RN = red nucleus.