UC Berkeley

Stress can dramatically alter the brain. Comprised of both neural and hormonal components, response to a perceived stressor can reorganize neural circuits, disrupt cell cycle and shift central control of a variety of systemic regulatory systems. While highly adaptive in many acute scenarios, if too prolonged or too extreme, the brain and bodily response to stress can be detrimental, such as in post-traumatic stress disorder, anxiety disorders and depression. Understanding how the basic environmental and psychological challenge of stress affects the brain is therefore important not only as a window into the basic neurobiology of adaptation to a changing environment, but also as an exploration into neuropathology. The following studies all address the issue of how the stress response alters the brain and thereby the body. Chapter 2 addresses the promotion of adult hippocampal neurogenesis by the basolateral amygdala, a brain region key to fear processing. Chapter 3 addresses how stress can interact with amygdala control of adult neurogenesis, depending on amygdala input for acute stress effects on neurogenesis but not for chronic stress effects. Chapter 4 focuses on how stress regulates sexual reproduction, exploring the role of a novel neuropeptide, gonadotropin-inhibitory hormone, in stress-induces suppression of sexual reproduction. All of the studies confirm the powerful effect of stress on the brain, and furthermore emphasize the complex nature of the relationship.