Thesis (doctoral)--Lund University, 1998. / Added t.p. with thesis statement inserted. Includes bibliographical references.

Thesis (doctoral)--Lund University, 1998. / Added t.p. with thesis statement inserted. Includes bibliographical references.

The major purpose of this study was to determine whether a relationship exists between cerebral laterality dominance and leadership behavior and traits. An additional purpose was to determine whether a relationship exists between cerebral laterality dominance and gender, ethnicity, and educational position.

Executive functions, potentially including the regulatory control of emotions and expressive fluency (verbal or design), have historically been associated with the frontal lobes. Moreover, research has demonstrated the importance of cerebral laterality with a prominent role of the right frontal regions in the regulation of negative affect (anger, hostility) and in the generation or fluent production of designs rather than verbal fluency (left frontal). In the present research, participants identified with high and with low levels of hostility were evaluated on a design fluency test twice in one experimental session. Before the second administration of the fluency test, each participant underwent the cold pressor stressor. EEG data collection took place before and after each experimental manipulation. It was hypothesized that diminished right frontal capacity in high hostiles would be evident through lowered performance on this cognitive stressor. Convergent validity of the "capacity model" was partially supported wherein high hostile men evidenced reduced delta magnitude over the right frontal region after exposure to a physiological stressor but failed to maintain consistent levels of right cerebral activation across conditions. The results suggest an inability for high hostile men to maintain stable levels of cerebral activation with stress after exposure to physiological and cognitive stress. Moreover, low hostiles showed enhanced cognitive performance on the design task with lower levels of arousal (heightened delta magnitude). In contrast, reduced arousal (heightened delta magnitude) yielded increased executive deficits in high hostiles as evidenced through increased perseverative errors on the design fluency task. / Ph. D.

Thesis (doctoral)--Universiteit Utrecht, 1995. / Summaries in English and French.

This experiment investigated sex differences in dynamic functional cerebral laterality effects on cardiovascular reactivity and dichotic listening in response to a stressor (a cold pressor). 120 right-handed undergraduate men (N = 60) and women (N = 60) underwent physiological measurements of systolic blood pressure (SBP), diastolic blood pressure (DBP), and heart rate (HR) before and after exposure to the cold pressor and a phonemic dichotic listening task. Functional cerebral laterality was assessed through the administration of the phonemic dichotic listening task. Group differences in dynamic functional cerebral laterality were predicted. Findings indicated a sex by focus interaction effect where men's, but not women's, systolic blood pressure increased significantly when focusing on sounds presented at the left ear during the dichotic listening task. Also, a compartmentalized, dynamic response in dichotic listening test performance was evidenced in both men and women (as both experienced increased accuracy at the right, but not left, ear), brought about as a function of the cold pressor. Men and women both evidenced increased cardiovascular reactivity, with men experiencing significantly more cardiovascular reactivity (SBP) than women in response to cold pressor pain. Women were also able to identify significantly more speech sounds presented to the left ear than men, and they were able to dynamically increase accuracy at the targeted ear identified within each focus group (left or right). Speech sounds processing (dichotic listening task) significantly decreased men's, but not women's, systolic blood pressure. These results contribute to the literature on sex differences in functional cerebral laterality. / Master of Science

This experiment was primarily designed to identify higher cortical correlates of cardiovascular arousal. Low- and high-hostile, right-handed, undergraduate men were identified using the Cook Medley Hostility Scale (CMHS). All participants (N = 30) completed the cold pressor paradigm. Cardiovascular (heart rate, systolic blood pressure, and diastolic blood pressure) and electroencephalographic (beta magnitude) data were collected before and after the stressor. As predicted, high-hostiles showed greater increases of heart rate and systolic blood pressure to the stressor relative to low-hostiles. The primary findings of this research include significantly greater beta magnitude recorded by the T3, relative to F7, electrode among low-hostiles. This may suggest that low-hostiles experience left-frontal disinhibition of left-temporal regions, thereby strengthening cardiovascular regulation during the cold-pressor stress. In addition, irrespective of condition, high-hostiles evidenced significantly greater beta magnitude at regions corresponding to the F7 and F8 electrodes. This perhaps suggests that high-hostiles have a relative inability to increase their rostral modulation of posterior systems related to cardiovascular activity/regulation. Low- and high-hostiles did not, however, evidence reliable differences in their ability to monitor cardiovascular arousal to the cold-pressor stress. Findings are discussed in terms of a systems approach, and pertinent future research is recommended. This research did not support the prominent neuropsychological theories of cardiovascular regulation proposed by Heilman et al. (1993) and Tucker and Williamson (1984). Rather, the results may suggest that right- and left-cerebral mechanisms may be primarily responsible for sympathetic and parasympathetic cardiovascular arousal, respectively. / Ph. D.

Research has indicated that the frontal and temporal lobes are involved in the mediation of heart rate and blood pressure. However, whereas these regions of the brain have been identified in the mediation of heart rate and blood pressure, the specific cerebral processes involved in determining the direction and magnitude of change in heart rate and blood pressure has not been adequately addressed. The present paper proposes that changes in the magnitude of cerebral activation between the left and right frontal and temporal lobes is partly that which determines the direction and magnitude of changes in heart rate and blood pressure. The present investigation sought to test part of this proposition, namely, that increasing magnitude of cerebral activity within the right anterior temporal region generates increasing levels of sympathetic control of heart rate and blood pressure and that the right lateral frontal region acts to inhibit sympathetic activity. A total of 45 right handed men, with no history of significant head injury, were exposed to 55 dB, 75 dB, and 90 dB white noise presentations. Right frontal lobe functioning was assessed by performance on the Ruff Figural Fluency Test (RFFT), with the participants scoring in the lower one-third classified as Low Fluency. Those scoring in the upper one-third were classified as High Fluency. Quantitative electroencephalography, measured at 19 electrodes sites arranged according to the International 10/20 System, as well as heart rate and blood pressure responses to white noise presentation were measured. Although the results failed to support any of the hypotheses concerning the effects of varying intensity of white noise on cardiovascular activity, partial support was found for the hypotheses that varying intensity of white noise would generate differential changes in high beta magnitude between the Low and High Fluency groups. The results are discussed in terms of support for the model being tested. Alternative explanations of the findings are also provided that demonstrate correspondence between the QEEG and cardiovascular data. Finally, limitations of the model and the methods of the present investigation are discussed and suggestions for improvement are provided. / Ph. D.