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Thesis (M.D.)--University of Adelaide, 1986. / Includes bibliographical references (leaves 317-350).

Diminished affective behavior is a frequently observed concomitant of cognitive dysfunction in the Human Immunodeficiency Virus (HIV), yet little is known about their relationship. A neuropsychological battery and electroencephalogram (EEG) recording was conducted on 29 HIV+ (Mage = 35.6 years, SD =5.36) and 30 HIV- (Mage =32.9 years, SD =6.39) women recruited from a family AIDS care program in South Florida. Using an emotion regulation paradigm, we compared event-related potentials (ERPs) following cues to view-neutral, view-negative and reappraise-negative images from the International Affective Picture System (IAPS). A group X instruction interaction was found for the P200 and early (400-1000 ms) late positive potential (LPP). Executive function, i.e., frequent task-switching predicted the attenuation of the early and late LPP following cues to up-regulate negative emotions. Greater response inhibition predicted attenuation of the LPP during the down-regulation of negative emotions. These findings suggest limited cognitive resources for the reappraisal of emotions in women with HIV. / by Roger Christopher McIntosh. / Thesis (Ph.D.)--Florida Atlantic University, 2012. / Includes bibliography. / Mode of access: World Wide Web. / System requirements: Adobe Reader.

Evidence in humans suggests that men are especially competitive with other men over resources and, if successful, are valued as attractive mating prospects by women. Previous studies also show that men experience an increase in testosterone following a win and a decrease in testosterone following a loss. If an increase in testosterone following a victory is an evolved physiological response aimed at readying a man for an increase in mating opportunities, then experimentally manipulating competitive outcomes should differentially affect men’s sex-drive. One-hundred thirteen men were randomly assigned to experience a win, a loss, or no competitive feedback. Participants’ sex-drive was gauged by their responses to photographs of women of differential attractiveness. Results showed that only single men exhibited a higher sex-drive in the winning condition, followed by the control and losing conditions, respectively. Limitations and practical applications to decreasing instances of rape and sexual coercion are discussed. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2014. / FAU Electronic Theses and Dissertations Collection

Despite extensive evidence documenting abnormal hypothalamic-pituitary-adrenal (HPA) axis functioning as a risk factor for the development of depression and other psychiatric disorders, and experimental evidence from acute stress manipulations, the effects of sustained cortisol alterations on clinically relevant cognitive-behavioural and neural processing remain poorly understood. The aim of this thesis was to characterise how non-acute changes in cortisol levels modify behavioural and neural biases implicated in stress-related disorders by following two complementary lines of evidence: firstly, by increasing cortisol via a direct pharmacological intervention; and secondly, by testing the ability of gut microbiota manipulations to alter cortisol reactivity. The first study found that sustained increases in cortisol following 10-day administration of hydrocortisone were associated with altered memory and emotional processing in healthy volunteers. Specifically, participants receiving hydrocortisone showed enhanced recognition of emotional words, while their neutral memory performance was unaffected despite lower parahippocampal and occipital activation during viewing and encoding of neutral pictures. Furthermore, we found that resting-state functional connectivity between limbic-temporal regions of interest (amygdala and hippocampus) and the striatum (head of the caudate), as well as frontal and prelimbic cortices was decreased. In contrast, hippocampal and visual processing during negative facial expressions, and functional connectivity between the amygdala and the brainstem at rest, were increased in the hydrocortisone versus placebo groups. Overall, these findings suggest that non-acute increases in glucocorticoids enhance processing of emotionally salient information in limbic-temporal regions, which may modulate further neural mechanisms of sensory and homeostatic relevance. Enhancements in declarative emotional memory following hydrocortisone also implicate the modulation of amygdalar-hippocampal interactions by cortisol. Conversely, neutral stimulus processing was found to be either reduced or unaffected across a number of cognitive and memory domains. A specific increase for negative processing was further supported by poorer self-reported well-being at the mid-point of the study in participants receiving hydrocortisone. In a separate study exploring the ability of prebiotic supplements to affect cortisol reactivity and emotional processing, a Bimuno-galactooligosaccharide prebiotic was found to reduce the waking cortisol response and increase positive versus negative attentional processing in healthy volunteers. While these effects were not found to be associated, they provide initial promising evidence of the ability to target the HPA axis and emotional processing via the gut microbiota in humans. Overall, this thesis supports the idea that stress-induced physiological changes after prolonged or repeated cortisol exposure are associated with neural and behavioural alterations, which in turn have been crucial in understanding neuropsychological mechanisms underlying psychiatric disease. A better stratification of the effects of sustained HPA axis alterations on psychiatrically relevant cognitive-emotional domains and neural mechanisms thus remains of high priority.

Bibliography: leaves 317-350 / 350 leaves : / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (M.D.)--University of Adelaide, 1986

Thesis (Ph. D.)--University of Oregon, 2004. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 113-126). Also available for download via the World Wide Web; free to University of Oregon users.

In addition to the reproductive benefits associated with outcompeting sexual rivals and being seen as an attractive mating prospect by women, research suggests that competition adaptively regulates men's sexual interest and behavior in preparation for mating opportunities following competitive outcomes, with victory leading to an increase in sexual interest and loss leading to a decrease in sexual interest. One hundred fifteen undergraduate men engaged in a contrived competitive task in which a third were led to believe that they won, a third were led to believe that they lost, and a third were led to believe that they neither won nor lost. Participants completed the Rape Attitudes and Beliefs Scale (RABS), which was used to test whether the effects of competition extend to men's proneness to sexual aggression. In addition, the current study attempted to replicate Gorelik and Bjorklund's (2015) finding that only single men's sexual interest is affected by competition. Results did not reveal an effect of competition on men's rape proclivity, although there were effects in the predicted direction on two of the RABS items. Gorelik and Bjorklund's (2015) effect of competition on men's sexual interest was not replicated. Limitations, implications for the understanding of the biology of sexual aggression, and directions for future research are discussed. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2015. / FAU Electronic Theses and Dissertations Collection

Summary: Salivary alpha-amylase: More than an enzyme - Investigating confounders of stress-induced and basal amylase activity (Dipl.-Psych. Jana Strahler) The hypothalamus-pituitary-adrenal (HPA) axis and the autonomic nervous system (ANS) are two of the major systems playing a role in the adaptation of organisms to developmental changes that threaten homeostasis. The HPA system involves the secretion of glucocorticoids, including cortisol, into the circulatory system. Numerous studies have been published that introduced salivary cortisol to assess HPA axis activity and therefore strengthens its role as an easy obtainable biomarker in stress research that can be monitored easily and frequently. Recent findings suggest a possible surrogate marker of autonomic activity due to autonomic innervation of salivary glands: salivary alpha-amylase (sAA). Up to date, additional methodological research is needed for a better understanding of the advantages and disadvantages of sAA activity in comparison to already established markers of ANS activity. The aim of the present thesis is to further our knowledge of confounders of sAA activity under basal and acute stress conditions and to strengthen the validity of this enzyme as an easy obtainable alternative for ANS testing. After introducing classical and modern stress concepts and stress system physiology (chapter 2), the reader is acquainted with anatomical basics of salivary gland innervation and secretion of salivary proteins, including sAA, due to autonomic innervation (chapter 3 and 4). Afterwards, a more nuanced review of methodological considerations of sAA determination shows gaps of knowledge concerning its usefulness as a marker of ANS activity (chapter 5). Given the fact that the integration of sAA into developmental and aging research is a relative recent phenomenon, several issues have to be addressed before a final conclusion could be drawn. Therefore, we conducted a series of studies incorporating these considerations regarding behavioral correlates of inter- and intraindividual differences in sAA activity with a special emphasis on older adults. Chapter 7 deals with sAA activity under psychological stress conditions in different age groups. Since vulnerability to disease and disease prevalence patterns change with age, it is important to investigate stress reactivity of people in different age groups. We therefore investigated children between 6 and 10 years, because childhood is a sensitive period of growth and development, and thus plays an important role for later life health. Young adults were included to represent the most studied human age group as a reference. Older adults between 59 and 61 years were investigated, because at this age the course is set for the further development of a person’s health in later life, and because autonomic stress responses in older age might be important determinants of cardiovascular and inflammatory aging. Our goal is to test for associations of sAA with more established stress system markers, i.e., salivary cortisol as outcome measurement of HPA reactivity, heart rate (HR) and heart rate variability (HRV) as markers for autonomic reactivity, and to directly compare these responses between different age groups across the life span. Secretion of sAA and cortisol was repeatedly assessed in 62 children, 78 young adults, and 74 older adults after exposure to a standardized psychosocial stressor, the Trier Social Stress Test. In addition, cardiovascular activity was measured in both adult groups. Older adults showed attenuated sAA, HR, and HRV responses. Furthermore, we found higher sAA but lower cortisol at baseline as well as lower sAA and cortisol responses in children. Age by sex interactions were observed only for cortisol with higher responses in older male participants. No associations between the parameters were found. Results in children and young adults confirm previous results. Overall, findings implicate sAA as an alternative or additional autonomic stress marker throughout the life span, with marked and rapid responsiveness to stress in three relevant age groups. The impact of age and chronic stress on basal sAA activity is the center of interest in chapter 8. We therefore assessed diurnal profiles of sAA and salivary cortisol in 27 younger and 31 older competitive ballroom dancers as well as 26 younger and 33 older age- and sex-matched controls. According to the Allostatic Load concept, repeated, non-habituating responses to social-evaluative conditions, which characterize the lives of competitive ballroom dancers, should be associated with stress system dysregulations. Furthermore, we expect to see an increased sympathetic drive associated higher overall alpha-amylase activity in older adults. Analyses revealed an elevated daily overall output of sAA in older adults while there was no effect of age on mean cortisol levels. Alterations of diurnal rhythms were only seen in younger male dancers showing a flattened diurnal profile of sAA and younger dancers and female older dancers showing a blunted diurnal rhythmicity of cortisol. Furthermore, we found a negative correlation between summary indices of basal sAA and the amount of physical activity. In conclusion, higher overall output of sAA in older adults was in line with the phenomenon of a “sympathetic overdrive” with increasing age. Furthermore, a lower output of sAA in people who are more physical active was in line with the hypothesis of an exercise-induced decrease of sympathetic activity. Taken together, results of chapter 7 and 8 show a clear impact of age on sAA activity, either under acute stress or basal conditions. One problem when integrating sAA into developmental and aging research is the use of adrenergic agonists and antagonists what is very common in older adults, i.e. antihypertensive drugs (AD). As well, the previously shown sympathetic overactivity that occurs with normal aging is associated with higher blood pressure (BP). Therefore, chapter 9 deals with a possible impact of high BP and AD on diurnal sAA activity in 79 older adults (33 normotensive adults, 16 medicated vs. 45 hypertensive adults, 34 medicated). Results showed a pronounced rhythm of sAA in all groups. Diurnal profiles differed significantly between men and women with men lacking the typical decrease of sAA in the morning and showing more pronounced alterations throughout the day. An effect of AD on sAA profiles and area under the curve values indicates that subjects not using AD´s show a heightened diurnal profile and a higher total output of sAA. Descriptively, this was also true for hypertensive older adults. Hypertensive subjects and those not using AD showed the highest diurnal output of sAA and the steepest slope. In sum, our results show an impact of antihypertensive medication and a difference between normotensive and hypertensive subjects on characteristics of diurnal sAA activity. Hence, findings are of particular interest in research using sAA as a prognostic indicator of pathological states and processes. Given the fact that hypertension was also shown to be associated with substantial changes of transmitters within the suprachiasmatic nucleus (SCN) - the “biological clock” that receives photic input from retinal glands via the retinohypothalamic pathway - and an altered output from the SCN to the sympathetic nervous system, we broaden the idea of a possible effect of different lighting conditions on morning sAA profiles in chapter 10. In a counterbalanced within-subjects design six men and 16 women of different ages collected sAA morning profiles on two consecutive days with leaving their shutters closed on the one day (= dark) and open their shutters on the other day (= bright). We were able to replicate earlier findings of light-induced changes of salivary cortisol with higher responses during the bright condition. On either day, women showed larger cortisol increases than men. Despite multisynaptic autonomic connections arising from the SCN projecting to multiple organs of the body, we could not find an effect of sunlight on sAA morning profiles. Evidence for circadian clock gene expression in human oral mucosa might account for this result and indicates that peripheral oscillators may act more like integrators of multiple different time cues, e.g. light, food intake, instead of a “master” oscillator (SCN). Results of chapter 7 to 10 provide clear evidence that sAA is heightened in states of autonomic arousal, i.e. stress, aging and hypertension, and that its circadian rhythmicity seems to be regulated rather integrative than directly via efferent input from hypothalamic SCN neurons. In chapter 11 this thesis tries to approach one central question: What is the biological meaning of the findings made? According to this enzyme´s anti-bacterial and digestive action short term changes might not have a biological meaning itself but rather reflect just a small part of multiple coordinated body responses to stressful stimuli. While the sympathetic branch of the ANS mainly stimulates protein secretion, the parasympathetic branch stimulates saliva flow. Acute stress responses might therefore be interpreted as reflecting predominant sympathetic activity together with parasympathetic withdrawal. The same mechanism could also be suitable for the finding of higher diurnal levels of sAA in older adults or hypertensive subjects reflecting a higher peripheral sympathetic tone in these groups. Diurnal profiles of sAA itself may reflect circadian changes in autonomic balance. Circadian rhythms are of great advantage since they enable individuals to anticipate. This pre-adaptation enables the individual to cope with upcoming demands and challenges. Our finding of a relationship between sAA and salivary cortisol what strengthens the relevance of glucocorticoids that were previously shown to be able to phase shift circadian rhythms in cells and tissue. Within a food-related context there is evidence that decreasing levels of sAA in the morning could reflect increases of feeling hungry since sAA systematically increases during food consumption and with the subjective state of satiety. So far, much more research is needed to identify underlying physiological mechanisms of circadian sAA rhythmicity. Taking the next step, future studies will have to focus on the integration of sAA assessment into longitudinal studies and different disease states to prove its applicability as a marker of sympathetic neural functioning in the genesis and prognosis of disease.

Thesis (M.Sc.)--University of Alberta, 2009. / A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Master of Science, Psychiatry. Title from pdf file main screen (viewed on August 13, 2009). Includes bibliographical references.