Fig. 4: Mapping chemoarchitecture to brainstem communities.

For each community (shown on the brainstem plot on the left as well as in Fig. 3b), a multiple linear regression model was fitted between 18 cortical neurotransmitter receptor and transporter density profiles and the community’s cortical weighted degree pattern (shown as surface plots as well as in Fig. 3c). Model fits (adjusted R²) are shown in the bar plot. Dominance analysis was applied to the independent variables (receptors and transporters) to determine which receptors/transporters were contributing most to the model fit²⁴. Percent contribution is shown in the heatmap. Receptor/transporter data were acquired from a PET atlas of neurotransmitter receptor/transporter densities in the human brain^21,23.