Browsing by Subject "HPA axis"
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Item Abnormal Recovery from Acute Stress in Huntingtons Disease Mice(2018-03-12) Zacharoff, Lori; Hamid, Arif; Engeland, William C; Dubinsky, Janet M; dubin001@umn.edu; Dubinsky, Janet MComparisons of hypothalamic dysfunction between Huntington’s Disease (HD) patients and rodent models of HD have not always yielded similar results. Cortisol levels in HD patients have been contradictory, with reports ranging from hypo- to hypercorticoidism of morning measurements. Initial reports of major elevations in circulating corticosterone levels in the R6/2 mouse model of HD have only been followed up in one other closely related model, the R6/1 mouse, and the results were not perfectly congruent. To determine if abnormal stress hormones were a characteristic of disease, we examined diurnal and stress-induced corticosterone levels in multiple HD mouse models.Item How Prenatal Maternal Stress Predisposes Offspring Toward Development of Gastrointestinal Disorders(2023-04-20) Boehmer, AbigailPrenatal maternal stress is highly prevalent in different circumstances, whether it’s depression, anxiety, an adverse major life event, or a difficult living situation. The stress experienced during pregnancy triggers a biological response in the mother which can transfer stress to the fetus through hormones like cortisol and adrenaline, serotonin, cytokines, reactive oxygen species, or the gut microbiota. This transfer of stress can induce alterations in fetal development, predisposing offspring of stressed mothers to developing gastrointestinal (GI) disorders such as colitis or Irritable Bowel Syndrome (IBS), specifically through gut dysbiosis. Ongoing research is necessary to determine the biological mechanisms of stress transfer, and how probiotic treatments may be used to correct dysbiosis and prevent or treat GI disorders.Item The impacts of social support and early life stress on stress reactivity in children and adolescents(2013-08) Hostinar, Camelia ElenaThe goal of the present study was to investigate the impacts of social support and early life stress on individual differences in HPA axis reactivity in children (ages 9-10) and adolescents (ages 15-16). The primary aims were: 1) to experimentally manipulate the provision of social support in the laboratory and examine its effect on levels of salivary cortisol in response to the Trier Social Stress Test for Children; 2) to investigate parenting quality variables that may moderate the social buffering effect based on coding of videotaped parent-child interactions; 3) to analyze the role of early life stress (orphanage-rearing versus birth family rearing) and current social network characteristics in predicting the cortisol response; and 4) to explore age and sex differences in stress reactivity and the social buffering of stress. A sample of 162 participants was recruited, roughly equally divided between the two age groups, experimental conditions (half were exposed to a parent support condition before the stress task, whereas half received support from a stranger), early life experience (adopted or non-adopted) and by gender. Analyses of cortisol stress responses revealed that in the non-adopted group parent support provided in the laboratory significantly dampened stress reactivity in children but not in adolescents when compared to the stranger support condition. Additionally, participants reared in orphanages showed atypical patterns of HPA reactivity and of responses to social support provided before the stressor. Implications and future directions are discussed.Item Psychophysiological Responses Among White Liberals to Discussing Race and Privilege(2022-08) Leneman, KeiraDiscussing race, racism, and privilege appears to be uncomfortable for many White individuals, as evidenced by a range of defensive emotional and behavioral responses. Understanding what leads to these reactions will be critical for interrupting and reshaping them. In this dissertation, I propose that physiological stress responses (e.g., fight-flight-freeze) may be a key uninvestigated component of defensive White reactions to critical race conversations. For this study, I employed an experimental design to test whether being randomly assigned to discuss race in a social evaluative context elicited more pronounced physiological and affective discomfort responses than in an active control condition. Physiological output measures indexing activity of both the hypothalamic-pituitary-adrenal axis and autonomic nervous system were collected across the experimental session and compared across treatment and control groups. Forty-two White, liberal emerging adults (33 female) participated in this study from March 2021 through April 2022. Overall, results suggested that discussing race and privilege in a socially evaluative context does elicit race-specific social evaluation concerns (i.e., concern of looking like a bad person and looking racist). However, neither physiological stress reactivity nor affective discomfort was significantly elevated in the group discussing race and privilege. In fact, physiological responses were minimal across the full sample. However, a significant interaction was found between treatment group and affective discomfort when looking at RSA reactivity to the speech. Participants that gave a speech about race and reported moderately low affective discomfort also displayed greater parasympathetic nervous system activation during the speech. Future analyses will explore hypotheses using qualitative analyses of video-recordings and transcripts from the session. More work is needed with a more diverse sample of White individuals (e.g., across age, socioeconomic status, ideology) as well as under more ecologically valid scenarios.