Seminar: "How Chronic Physical and Social Stress Can Affect Behavior and Neurophysiology of the BNST" - Thomas Degroat

EAB Dissertation Defense Seminar

"How Chronic Physical and Social Stress Can Affect Behavior and Neurophysiology of the BNST"

Thomas Degroat

PhD Candidate

Graduate Program in Endocrinology and Animal Biosciences

Chronic stress is well known to lead to the development or worsening of psychiatric disorders, particularly mood disorders, such as major depressive disorder. In this dissertation, I elucidate how chronic stress leads to depressive-like avoidant behaviors in mice that is related to changes in the neurophysiology of the anterodorsal bed nucleus of the stria terminalis (adBNST). First, I analyzed how physical stressors affected males and females differently through behavior tests, electrophysiology, and RNA sequencing. I discovered that the physical stressors generally increased avoidant behaviors, though this was dependent on the estrous stage in the females and it did not appear to be related to the transcriptome or the M-current of NPY+ neurons in the adBNST. Next, I refined the previous experiment and expanded upon it by continuing the physical stress experiments and redoing the RNA sequencing with new methods and performing more electrophysiology in the adBNST in CRH+ cells. I discovered that the adBNST transcriptome was affected by stress, although the males were more sensitive, and that this was paired with a suppression of the M-current in males and a suppression of excitatory post-synaptic potentials in females. Furthermore, I continued my studies by repeating the behavioral assays and RNA sequencing but with a social stress paradigm. I discovered that males and females respond differently to the stress and that again the male adBNST transcriptome was more sensitive to stress. In summary, my results indicate that there are major sex differences in how the adBNST reacts to stress and that this is dependent on the types of stress.