Precentral gyrus (PCG) parcellation. This five-region PCG parcellation was used to estimate functional motor connectivity signatures for each subject. The parcellation was derived from test-retest resting state data collected from an independent sample of 20 neurotypical adults, (Nebel et al., 2014) and the parcels were initially eroded to reduce the influence of boundary voxels on between-parcel connectivity estimates. These functional subdivisions are named based on their location within the PCG: (1) Dorsomedial ("DM"), (2) Dorsolateral ("DL"), (3) Anterior Lateral ("AL"), (4) Posterior Lateral ("PL"), and (5) Ventrolateral ("VL"). (A) Anterior (front) view, (B) Left side view, (C) Superior (birds-eye) view.