Brain–body states as a link between cardiovascular and mental health

Numerous studies in humans have demonstrated a strong link between heart and brain function at different timescales. We conceptualize this functional coupling using different dimensions of brain-body states, formed through the integration of the central and peripheral nervous systems (PNS and CNS, respectively). Using concepts from dynamical systems theory, we discuss how patterns of brain-body dimensions traverse a state space. Attractors signify stable configurations, which we categorize as micro-, meso-, or macro-states according to their duration and reversibility. These reflect different underlying mechanisms, such as neural interactions, hormonal signaling, and structural plasticity. Longer-lasting states restrict the space of possible (shorter-term) brain-body states underlying the mutual dependence of cardiovascular and brain function over the lifespan and in the development of diseases such as hypertension and depression. These considerations, which can be further generalized to include immunological and metabolic dimensions of brain-body states, have broad conceptual and clinical implications.