Keynote: The Brain on Stress: Importance of the Social Environment for Brain and Body Health
Speaker: Bruce S. McEwen, PhD
Format: Video & Slides

The brain is the central organ of stress and adaptation to stress because it perceives and determines what is threatening, as well as the behavioral and physiological responses to the stressor by the active process of adaptation. Reflecting how each person's life history contributes to their well-being, the adult, as well as developing brain, possesses a remarkable ability to show structural and functional plasticity in response to stressful and other experiences, including neuronal replacement, dendritic remodeling, and synapse turnover. This is particularly evident in the hippocampus, where all three types of structural plasticity have been recognized and investigated, using a combination of morphological, molecular, pharmacological, electrophysiological and behavioral approaches. The amygdala and the prefrontal cortex, brain regions involved in anxiety and fear, mood, cognitive function and behavioral control, also show structural plasticity. Acute and chronic stress cause an imbalance of neural circuitry subserving memory, decision making, anxiety and mood that can increase or decrease expression of those behaviors and behavioral states. In the short term, such as for increased vigilance in a threatening environment, these changes may be adaptive; but, if the danger passes and the behavioral and systemic stress states persist along with the changes in neural circuitry, such maladaptation may need intervention. This is where mindfulness and meditation fit in and examples will be given of human brain imaging studies in which such interventions change brain structure and function in parallel with decreased disease symptoms! Moreover, adverse early life experiences, interacting with certain genes, produce lasting effects on brain and body via epigenetic mechanisms. While disease prevention is most important, the plasticity of the brain gives hope for therapies of disorders that take into consideration brain-body interactions and the important ability of the brain to change itself.