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

Area of Science:

• Neuroscience
• Comparative Biology
• Systems Neuroscience

Background:

• Resting-state functional magnetic resonance imaging (fMRI) studies have identified evolutionarily relevant brain networks using time-averaged analyses.
• However, the dynamic, second-by-second evolution of fMRI network activity and its cross-species conservation remain largely unexplored.

Purpose of the Study:

• To investigate whether the dynamic organization of resting-state fMRI network activity is conserved across mammalian species.
• To identify common dynamic principles governing brain network organization across phylogeny.

Main Methods:

• Applied frame-wise clustering to fMRI time-series data from awake male macaques and humans.
• Analyzed the dynamic transitions between intrinsic fMRI coactivation modes (C-modes).
• Compared dynamic features and neuroanatomical homology of C-modes across species, including rodents.

Main Results:

• Identified 4 dominant, neuroanatomically homologous fMRI coactivation modes (C-modes) in macaques and humans, with 3 plausibly present in rodents.
• Observed species-invariant dynamic features of C-modes, including preferred occurrence during specific global signal fluctuation phases and infraslow coupled oscillator dynamics.
• Demonstrated that dominant C-mode occurrence reconstructs static fMRI connectome organization and predicts connectivity gradient rankings across species.

Conclusions:

• Revealed a set of species-invariant principles governing the dynamic organization of fMRI networks in mammals.
• Established a framework for relating fMRI network findings across the mammalian phylogenetic tree by focusing on dynamic organization.