Dissertation
Top-down modulation of stress response patterns through the midbrain periaqueductal gray
University of Iowa
Doctor of Philosophy (PhD), University of Iowa
Summer 2023
DOI: 10.25820/etd.006990
Abstract
The stress response is a broad, non-specific process which evolved to increase fitness during a period of threat. Survival of an organism depends on proper function of these systems both normally and during periods of adversity. A proper mobilizing of the stress response requires behavioral, endocrine, and physiologic processes, all of which have been shown to be disrupted in stress-related psychiatric disorders. While stress-induced mental illness is prominent among the population, little is known about the neural circuits modulating various aspects of the stress response. Neuroanatomical studies have described a wide array of projections from the prefrontal cortex and amygdala, including to midbrain structures such as the periaqueductal gray. However, the complete circuits, as well as the functional role these connections play, are still unclear. The idea has existed that stress responses display distinct patterns, involving the differential induction of behavioral, HPA, and autonomic features commensurate with task demands. Since the inception of this theory, less attention has been paid to understanding the neurobiological support for this idea. The sum of previous work from other research groups, including ours, raises the prospect that the brain coordinates features of stress responses as based upon the particular coping style employed by the organism. The goal of these experiments was to further characterize neural circuits modulating stress response patterns, and to provide a holistic picture of their functional significance in producing stress response patterns.
Details
- Title: Subtitle
- Top-down modulation of stress response patterns through the midbrain periaqueductal gray
- Creators
- Timothy D Skog
- Contributors
- Jason J Radley (Advisor)Stephanie C Gantz (Committee Member)Alan K Johnson (Committee Member)Ryan T LaLumiere (Committee Member)Hanna E Stevens (Committee Member)
- Resource Type
- Dissertation
- Degree Awarded
- Doctor of Philosophy (PhD), University of Iowa
- Degree in
- Neuroscience
- Date degree season
- Summer 2023
- DOI
- 10.25820/etd.006990
- Publisher
- University of Iowa
- Number of pages
- xiii, 108 pages
- Copyright
- Copyright 2023 Timothy David Skog
- Language
- English
- Date submitted
- 06/12/2023
- Description illustrations
- illustrations, graphs
- Description bibliographic
- Includes bibliographical references (pages 92-108).
- Public Abstract (ETD)
- Stress is a universal experience. While at times it can be good to have a little stress to accomplish tasks, avoid uncomfortable situations, or escape threatening environments, too much stress for too long can be damaging to our overall health. Chronic (prolonged) or extreme stress can lead to development of diagnosed psychiatric disorders such as depression, anxiety, or post-traumatic stress disorder. These conditions still lack effective treatments that improve patients’ quality of life. However, improved therapies cannot be developed without a better understanding of the neural mechanisms underlying these processes. Therefore, our research focuses on describing how different regions in the brain communicate to control how organisms respond to stress. By understanding these mechanisms in non-pathological conditions, we can better understand the systems affected by chronic and extreme stress. An important aspect to dealing with stress is how one responds to the threat. Coping strategies are actions taken to engage with and mitigate stressors. Active strategies involve engaging with perceived or real threats, whereas passive coping involve inaction. While both can be useful in certain situations, utilizing the improper strategy is a hallmark of stress-induced conditions. Here, we demonstrate that circuits coordinate behavior with our bodily processes (i.e., heart rate, hormone secretion) in response to stressors. We found that one circuit produced active coping strategies and proper activation of stress systems in the body whereas another promoted passive coping strategies associated with pathology. Together, these studies provide a neurobiological basis for selection of different stress response strategies.
- Academic Unit
- Interdisciplinary Graduate Program in Neuroscience
- Record Identifier
- 9984454541602771
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