Fig. 1: Methodology of gradient generation.
From: Tau follows principal axes of functional and structural brain organization in Alzheimer’s disease
a Our multi-modal input data included dMRI, fMRI, and PET images, co-registered to a high-resolution custom brain atlas. b The resulting modality-specific connectomes or covariance matrices were transformed into a similarity matrix and subjected to diffusion map embedding. The resulting gradients make up a low-dimensional coordinate space. The interpretation of gradients (as applied in the current work) is visually compared to the traditional atlasing techniques, showing overlapping modes of connectivity similarity vs. discrete regions. c The main analyses involve either cohort-level investigations using group-wise connectomes/covariance matrices (Spearman’s rank coefficient ρ between different modalities) or individual participants’ connectomes (between-group differences based on t-statistics).
