What changes on the board when power moves from smooth patterns to fine-grained ones? In harmonic-mode, mode 1 swings the two hemispheres in opposite phase, while mode 2 moves both together along the front–back axis.
Try this Switch regime to standing-wave-mix and drag psychedelic-shift from 0 to 100 while it runs. The smooth left–right swing gives way to a fine-grained pattern.
About this model Where it ends up
Selen Atasoy, Isaac Donnelly and Joel Pearson (Nature Communications, 2016) proposed that brain activity decomposes into connectome harmonics: the eigenvectors of the graph Laplacian of the brain's structural wiring, ordered from smooth whole-brain patterns to fine-grained ones. Later work by Atasoy and colleagues reported that LSD moves power from low harmonics to high ones. This model is adapted from Adam Safron's connectome_harmonics demo at CIMC.
It illustrates the idea rather than computing it. The 48 regions sit on two rings per hemisphere, each wired to one nearby region, with a few links across the midline. The spatial patterns are written as functions of position (mode 1 is a left–right gradient, mode 2 a front–back one, higher modes are sine–cosine checkerboards), not computed as eigenvectors of this graph's Laplacian, and higher modes are given faster frequencies.
There are four regimes. harmonic-mode plays one pattern as a standing wave. standing-wave-mix blends modes 1, 7 and 20, and psychedelic-shift moves weight from mode 1 to mode 20. kuramoto-sync runs phase oscillators with global mean-field coupling of strength coupling-k. wave-diffusion relaxes each region toward the chosen pattern with damping.
