brains. PC1 is associated with primary sensorimotor cortices, with relative differential expression in precentral (motor) and postcentral (somatosensory) cortex, Heschl’s gyrus (primary auditory) and primary and secondary visual areas. Confirmation of the visual cortex enrichment by ISH for several synaptic transmission-associated genes highly correlated to PC1 is shown in Supplementary Fig. 7. PC2 has areal selectivity for posterior orbital, paraolfactory and subcallosal gyri in the frontal lobe, the temporal pole, and the primary visual cortex. PC3 is primarily differential in frontal cortex compared to temporal and occipital cortex. These first three components accounted for a large amount of the variance (PC1: 58% in Brain 1, 42% in Brain 2; PC2: 10% in Brain 1, 11% in Brain 2; PC3: 5% in Brain 1, 8% in Brain 2; Supplementary Fig. 8). The spatial organization of the first three principal components was highly correlated between brains (Pearsonr = 0.71 for PC1, 0.51 for PC2 and 0.70 for PC3).
