Resting state fMRI connectivity mapping across species: Challenges and opportunities

Resting-state fMRI (rs-fMRI) has been extensively used to map interareal functional connectivity in the human brain. Fostered by the need to link spatiotemporal scales and investigate the neural basis of large-scale network (dys)connectivity, this approach is being increasingly implemented in physiologically accessible species such as rodents and nonhuman primates. Here, we review and critically appraise challenges and opportunities in cross-species application of rs-fMRI as a bridge in translational and systems neuroscience. We discuss how the macroscale functional organization of the mammalian brain follows evolutionarily conserved principles across species, such as the presence of convergence in rs-fMRI network organization, a phylogenetically conserved hierarchical axis of cortical connectivity spanning unimodal-polymodal regions, and broadly conserved fMRI coactivation dynamics. As increasingly sophisticated perturbational, computational, and recording tools are becoming available to neuroscientists, the application of rs-fMRI across species provides a unique research platform to probe the large-scale functional organization of the mammalian brain in health and disease.