Supplementary Figure 1: Group-averaged cortical T1w/T2w maps exhibit interspecies homology and interhemispheric symmetry.

(a) Unparcellated group-averaged (N=339) T1w/T2w map in human cortex visualized bilaterally on an inflated cortical surface. (b) Unparcellated group-averaged (N=19) T1w/T2w map in monkey cortex visualized bilaterally on an inflated cortical surface. (c) Primary sensory (visual, V1; auditory, A1; somatosensory, S1) and primary motor (M1) homologues in human and monkey cortex, corresponding to the four bordered areas in panels a and b, exhibit high T1w/T2w map values relative to the average value computed across all higher-order sensory and association (Non-Primary) areas. Grey bars mark the standard error on the mean. The low T1w/T2w map value found in monkey area A1 (relative to human area A1) is likely driven by the size and lack of spatial specificity of the corresponding M132 parcel which extends deep down into temporal cortex. Note that human Brodmann area 3 is further subdivided into areas 3a and 3b in the HCP parcellation, the latter which was used for this analysis. (d) Functional networks derived from resting-state functional connectivity from the Human Connectome Project (HCP). Cortical areas are parcellated using the HCP multi-modal parcellation (MMP1.0). We assigned each region to a functional network using a community detection method applied to resting-state fMRI data from the HCP, and designated functional labels to networks, including three sensory and five association, that align with previously reported functional networks (with abbreviations labeled in Fig. 1b): Auditory (AUD), Visual (VIS), Somatomotor (SOM), Dorsal Attention (DAN), Frontoparietal (FPN), Ventral Attention (VAN), Default (DMN), and Cingulo-Opercular (CON).