Fig. 2: Functional and structural connectivity gradients are altered in AD.
From: Tau follows principal axes of functional and structural brain organization in Alzheimer’s disease
a The first three functional connectivity gradients (GFC) projected onto the left-brain surface, extracted from the cohort-level connectome (average of n = 213 connectomes). Similar colors along the purple-yellow scale represent similar brain-wide connectivity patterns. The bar plots represent the corresponding network-specific average gradient scores ± standard error of the mean (SEM). G1FC, G2FC, and G3FC explained 55, 17, and 9% of the information in functional connectome data, respectively. b Coordinate system spanned by the first two gradients based on group-level functional connectomes (average of n = 103, 35, and 75 connectomes, respectively), indicating G1FC contraction with unimodal and transmodal (DMN) regions moving closer to each other in CI participants. c Histogram of gradient scores reflected global G1FC contraction with an expansion of scores centered around zero. d Between-group comparisons (green: CN A+ [n = 35] vs. controls [n = 101]; orange: CI [n = 72] vs. controls [n = 101]) of network-based G1FC alterations (asterisks represent significant t-statistics at the network-level with two-sided P < 0.05, adjusted for age, sex, and APOE-ε4) using a group-level (left) or full cohort-level (right) gradient realignment strategy. Word clouds of NeuroSynth cognitive terms associated with regions with positive (red) or negative (blue) t-statistic G1FC differences between diagnostic groups (using cohort-level realignment strategy). e G1SC, G2SC, and G3SC explained 28, 20, and 9% of the information in structural connectome data, respectively. f Coordinate system spanned by the first two gradients. g Histogram of G1SC. h Between-group comparisons (green: CN A+ [n = 35] vs. controls [n = 102]; orange: CI [n = 72] vs. controls [n = 102]) of network-based G1SC alterations and corresponding word clouds. Results are displayed for the left hemisphere; Supplementary Fig. 1, 3, and 7 show right hemisphere projections and group differences. Source data are provided as a Source Data file. Abbreviations: CN cognitively normal, CI cognitively impaired, FC functional connectivity, G gradient, SC structural connectivity.
