Fig. 7: Association between principal gradient shifts and NET density.
From: Methylphenidate reorganizes cortical hierarchy through dopaminergic modulation
a Cortical surface maps showing the statistical differences (t-score) in the principal functional connectivity gradient between methylphenidate (MP) and placebo (PL), displayed on lateral (top) and medial views of the left hemisphere. b Regional norepinephrine transporter (NET) density map derived from PET data, displayed on corresponding cortical views. The null distribution of spatial correlation coefficients was generated via spin test (10,000 permutations). The observed empirical correlation between principal gradient shifts and NET density across 438 parcels is indicated by a red horizontal arrow. A significant correlation was found (spin-test p = 0.0008), indicating that regions with higher NET density had stronger MP-induced shifts in the principal gradient. All statistical tests are two-sided.
