LAUSR

The move from the concept of homeostasis to that of allostasis has led reactivity stress research to widen the object of its investigation: from the brief physiological response that occurs when one is facing a stressor to what happens when one is anticipating or recovering from a stressor. A paradigmatic example is represented by perseverative cognition, during which human beings react "as if" they were constantly facing a concrete stressor. The core idea behind this review is that the cognitive inflexibility that characterizes perseverative cognition is reflected in both our body (by increased autonomic nervous system rigidity assessed by heart rate variability; HRV) and our brain (by reduced prefrontal-amygdala functional connectivity). This is a review of studies conducted in different settings (laboratory, daily life), populations (healthy, major depression, generalized anxiety), location (United States, Europe), and age groups (children, adults) that consistently replicated the association between autonomic, subjective, and behavioral measures of cognitive inflexibility during perseverative cognition. Moreover, compelling neuroimaging data suggest that HRV reduction from pre- to post-induction of perseverative cognition is associated with both structural and functional brain abnormalities reflecting impaired prefrontal inhibitory control over subcortical structures (e.g., diminished prefrontal-amygdala functional connectivity). The integration of neuroscience techniques with clinical autonomic research has advanced our understanding of the neurobiology of brain-heart interaction during perseverative cognition, potentially yielding to more effective treatment packages. This is clinically relevant if one considers that perseverative cognition is a pervasive transdiagnostic factor that carries prognostic risk for both psychological and somatic health.