Abstract: Series 106, Lecture 7
The Harvey Lectures Series 106 (2010—2011)
Lecture #7: Thursday, May 19, 2011 — Time and Location
Sex, Stress and the Brain:
Hormone Actions Above the Hypothalamus Via Novel Mechanisms
Bruce S McEwen, PhD
Alfred E Mirsky Professor and Head
Harold and Margaret Milliken Hatch Laboratory of Neuroendocrinology
The Rockefeller University
New York, New York
The adult brain is much more resilient and adaptable than previously believed, and adaptive, structural plasticity involves growth and shrinkage of dendritic trees, turnover of synapses and limited amounts of neurogenesis in the forebrain, especially the dentate gyrus of the hippocampal formation. Stress and sex hormones mediate adaptive structural plasticity in hippocampus, prefrontal cortex and amygdala, brain regions involved in memory, decision making, emotional regulation and impulse control. These hormones exert their effects on brain structural remodeling through classical and indirect genomic mechanisms, as well as non-genomic molecular mechanisms and they do so in collaboration with neurotransmitters and other intra- and extracellular mediators. Early life stress and brain sexual differentiation determine the nature and degree of this plasticity. Because hormones influence so many aspects of brain structure and function and because hormone secretion is governed by the cognitive and emotional brain acting through the hypothalamus, the role of brain plasticity must be considered in understanding how the social and physical environment “gets under the skin” to affect brain and body resilience and vulnerability to disease.