Evolutionarily conserved fMRI network dynamics in the mouse, macaque, and human brain

Evolutionarily relevant networks have been previously described in several mammalian species using time-averaged analyses of fMRI time-series. However, fMRI network activity is highly dynamic and continually evolves over timescales of seconds. Whether the dynamic principles that govern intrinsic fMRI network fluctuations are conserved across mammalian species remains unclear. Using frame-wise clustering of fMRI time-series, we find that fMRI network dynamics in awake macaques and humans is characterized by recurrent transitions between a set of 4 dominant, neuroanatomically homologous fMRI coactivation modes (C-modes), three of which are also plausibly represented in the rodent brain. Importantly, in all species the identified C-modes exhibit species-invariant dynamic features, including intrinsic infraslow dynamics and preferred occurrence at specific phases of global fMRI signal fluctuations. Moreover, C-modes occurrence rates in awake humans, macaques and mice reflect temporal trajectories of least energy and predicts ranking of corresponding functional connectivity gradients. Our results reveal a set of species-invariant principles underlying the dynamic organization of fMRI networks in mammalian species, and offer novel opportunities to relate fMRI network findings across the phylogenetic tree. ### Competing Interest Statement The authors have declared no competing interest.