Fig. 1: The principal cortical gradient during baseline and nitrous oxide.

a Visualization of the principal gradient values of the cortex. The color scale represents gradient values, with warm colors indicating transmodal and cool colors indicating unimodal. b Histogram of principal gradient derived from whole-brain voxels. c Voxel-based contrast of the gradient values for nitrous oxide vs. baseline. Paired t-test (two-tailed) was performed for nitrous oxide condition (n = 16) against its own baseline conditions (n = 16), pFWE <0.05 corrected. d Individual gradient values extracted from regions showing statistical significance in (c). N2O nitrous oxide, MOG middle occipital gyrus, TPJ temporoparietal junction, SFG superior frontal gyrus, PCC posterior cingulate cortex.