Connectivity-derived STN segmentation and MER analysis. (A) 7 T T2 MRI of an example patient showing the STN in coronal and axial planes. d: dorsal, v: ventral, l: left, r: right. (B) 7 T T2 MRI registered to the diffusion MRI and the connectivity-derived STN segmentation; motor-connected STN (mc-STN, blue) with projections to the cortical motor areas (transparent blue) and non-motor-connected STN (nmc-STN, green) in the same example patient. The black pointer indicates the dorsal STN motor subdivision. Images are aligned to the commissural line. (C) Baseline-corrected power spectrum for mc-STN and nmc-STN. MUA calculated as mean power >300 Hz. The solid line showing mean and the shading showing standard error. (D) Mean MUA at each recording site, aligned to the active location site (grey shading). Mc-STN in blue and nmc-STN in green. The error bars show standard error. Stippled black line: 1-log P-value from ANOVA calculated at each site. The solid black line, which is the same for ANOVA, calculated in a three-site sliding window. The stars denote significant differences after multiple comparison correction. mc, motor-connected; nmc, non-motor-connected; STN, subthalamic nucleus; MER, microelectrode recording; MUA, multi-unit activity. Sample size MUA: total recordings n = 149 (25 patients, 3 recordings per hemisphere covering the active DBS electrode contact site, for 1 patient the most dorsal active contact site was used, which resulted in 2 recordings for that hemisphere); motor-connected STN recordings n = 27; non-motor-connected STN recordings n = 122.
