What brain systems mediate stress-related coping behaviors that impact health, including behaviors related to tobacco use, diet and physical activity, and alcohol consumption? Are the same putative appraisal systems of the brain that interact with visceral control loops also important for regulating such stress-related health behaviors? If so, do behavioral stress-reduction or stress-regulation interventions designed to promote health do so by affecting their functionality? How are stress-related interactions between multiple visceral control loops of the body represented in the brain? Psychological stressors evoke complex and coordinated changes in multiple physiological systems, including inter-related changes neuroendocrine, autonomic, immune and other systems. While these systems exhibit their own feed-forward and feedback neuro-visceral loops, it is still not clear how the brain coordinates or registers their interactive crosstalk. Nor is it clear how their crosstalk affects the functionality of systems important for encoding and appraising psychological stressors. The field still lacks metrics that accurately characterize multisystem interactions and the bidirectional flow of integrated information between brain and body over any time scale, especially in the context of health and disease. Could ‘big data’ and pattern classification methods (e.g., machine learning techniques) help to better quantify and measure stress-related appraisal processes and appraisal-visceral interactions at the level of the brain? If so, might such computational methods also enable us to better link these brain-based processes and interactions to objective physical health outcomes (e.g., predict future disease or mortality) in representative and population-based samples, which are more typical of traditional health psychology and disease epidemiology research? Are stress and emotion or emotion regulation processes dissociable at the level of the brain? We have an incomplete understanding of the relationships between psychological stress and emotional processes. At the level of the brain, it is becoming increasingly clear that the brain systems important for mediating emotion and emotion regulation (e.g., mPFC, amygdala, PAG) are also involved in processing psychological stressors and regulating peripheral physiological functions important for physical health. However, the overlapping and dissociable functions of brain systems related to emotion and stress remain unclear. How does early life stress influence the functionality of brain systems for appraisal and visceral control in later life? Early life stress increases risk for multiple adverse health outcomes in adulthood, but we still have a poor understanding of the brain bases of this risk. Human neurodevelopmental studies are needed; such studies should include assessments of early life stress and track later changes in stress-related brain functionality and health. What are the precise roles of subcortical regions in linking appraisal-related neural activity to physiological responses important for health? Most findings to date have focused on large structures, often in the cortex or subcortical telencephalon (e.g., the amygdala). However, extensive animal work relates stress and visceral control functions to changes in smaller structures, such as the hypothalamus, PAG, bed nucleus of the stria terminalis, and habenula. The relative paucity of human stress-related findings in these areas may result from artifacts in neuroimaging studies rather than true inter-species differences. As the quality and resolution of neuroimaging data improves, stress-imaging studies can re-examine the roles of these structures in human stress, emotion, and health.
|
