Fig. 4: θ–α SPC neurons are localized in the posterior part of STN.

A Subthalamic spatial density maps (radius of 1 mm) across frequency bands. STN regions sampled by microelectrode recordings are depicted as white overlay. The size of the spheres represents the degree to which t-SPC events are localized in a 1 mm radius around the center of each sphere. To augment the readability of the visualization, we adopted the logarithmic scale for the spatial density. The anatomical reference of the frame shows the relative orientation between the dorsal (D), lateral (L), and posterior (P) directions and the first three principal components directions (PC1: anterior-posterior axis, PC2: dorso-ventral axis and PC3: medio-lateral). θ (red), α (dark orange), and β (yellow). Black and magenta vertical dashed lines denote auditory cue (AC) and speech production (SP) windows. Cross indicates the spatial centroid of the t-SPC event locations. θ₁, α₁, α₂, and β₁ depict the location of peaks of the t-SPC spatial density. B Spatial density of the t-SPC events mapped along the three principal component axes. The intersection of the two dashed black lines represents the STN center of mass. The radius of the pie-chart represents the t-SPC spatial density across bands. The black contour delineates the STN border as depicted by the DISTAL atlas. Note that principal component scores represent actual physical distances in mm.