Cortical and subcortical mapping of the allostatic-interoceptive system in the human brain: replication and extension with 7 Tesla fMRI

Abstract

AbstractThe brain continuously anticipates the energetic needs of the body and prepares to meet those needs before they arise, a process called allostasis. In support of allostasis, the brain continually models the internal state of the body, a process called interoception. Using published tract-tracing studies in non-human animals as a guide, we previously identified a large-scale system supporting allostasis and interoception in the human brain with functional magnetic resonance imaging (fMRI) at 3 Tesla. In the present study, we replicated and extended this system in humans using 7 Tesla fMRI (N = 91), improving the precision of subgenual and pregenual anterior cingulate topography as well as brainstem nuclei mapping. We verified over 90% of the anatomical connections in the hypothesized allostatic-interoceptive system observed in non-human animal research. We also identified functional connectivity hubs verified in tract-tracing studies but not previously detected using 3 Tesla fMRI. Finally, we demonstrated that individuals with stronger fMRI connectivity between system hubs self-reported greater interoceptive awareness, building on construct validity evidence from our earlier paper. Taken together, these results strengthen evidence for the existence of a whole-brain system supporting interoception in the service of allostasis and we consider the implications for mental and physical health.Significance StatementWe used ultra-high field 7 Tesla fMRI to replicate and extend a large-scale brain system supporting interoception and allostasis, entwined processes crucial to the core brain function of coordinating and regulating the internal systems of the body. In particular, we mapped the subcortical extents of this system, several of which are small brainstem nuclei only recently delineated at 7 Tesla. Our findings suggest that investigations of distributed brain networks should not be restricted to the cerebral cortex. We emphasize bodily regulation as a whole-brain phenomenon and highlight its implications for mental and physical health.