Host in the machine: A neurobiological perspective on psychological stress and cardiovascular disease

Abstract

Psychological stress still attracts scientific, clinical, and public interest because of its suspected connection to health, particularly cardiovascular health. Psychological stress is thought to arise from appraisal processes that imbue events and contexts with personal significance and threat-related meaning. These appraisal processes are also thought to be instantiated in brain systems that generate and control peripheral physiological stress reactions through visceral motor (brain-to-body) and visceral sensory (body-to-brain) mechanisms. In the short term, physiological stress reactions may enable coping and adaptive action. Among some individuals, however, the patterning of these reactions may predict or contribute to pathology in multiple organ systems, including the cardiovascular system. At present, however, we lack a precise understanding of the brain systems and visceral control processes that link psychological appraisals to patterns of stress physiology and physical health. This understanding is important: A mechanistic account of how the brain connects stressful experiences to bodily changes and health could help refine biomarkers of risk and targets for cardiovascular disease prevention and intervention. We review research contributing to this understanding, focusing on the neurobiology of cardiovascular stress reactivity and cardiovascular health. We suggest that a dysregulation of visceral motor and visceral sensory processes during stressful experiences may confer risk for poor cardiovascular health among vulnerable individuals. We further describe a need for new interpretive frameworks and markers of this brain-body dysregulation in cardiovascular behavioral medicine. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Figure 1

Simplified schematic of heterarchical organization of neural influences on the cardiovascular system and targets for visceral homeostatic control. Shown are interacting behavioral, effector, and organ targets of visceral homeostatic control. Behavioral targets correspond to brain-based predictive metabolic support commands for mental and overt behavioral action. These behavioral targets can be conditioned by appraisal processes, as mediated by interactions between rostral and caudal neural systems, including cortical, limbic, midbrain, and brainstem regions. Effector targets correspond to levels of heart rate and blood pressure necessary to sustain metabolic support of tissues. Organ targets correspond to local maintenance of ion and fluid balance in the heart and vasculature. In this heterarchical organization, systems can interact directly and indirectly. As a consequence of this organization, autonomic outflow that is locally organized to maintain homeostasis can be interrupted, bypassed, or influenced by caudal and rostral neural systems to reset or produce ‘non-homeostatic’ target organ state changes (e.g., in the heart and vasculature).

Figure 2

A heuristic schematic of the pathways that influence stressor-evoked physiological (e.g., cardiovascular) reactivity. Specific types of reactivity linked to disease risk are conceptualized as outcomes of ‘visceral prediction errors,’ wherein there is a mismatch between anticipated and actual metabolic needs of a context or demand appraised as threatening. Appraisals that generate threat-related meaning are updated according feedback provided by the outcomes of predictive processes.