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Thesis (Ph.D.)--Hong Kong University of Science and Technology, 2008. / Includes bibliographical references (leaves 368-377). Also available in electronic version.

Thesis (M.Phil.)--Hong Kong University of Science and Technology, 2008. / Includes bibliographical references (p. 81-84). Also available in electronic version.

Thesis (Ph. D.)--University of Washington, 1998. / Vita. Includes bibliographical references (leaves [126]-138).

The use of incremental and repeated exposures regimens have been put forth as effective means to mitigate visually induced motion sickness based on the Dual Process Theory (DPT) (Groves & Thompson, 1970) of neural plasticity. In essence, DPT suggests that by incrementing stimulus intensity the depression opponent process should be allowed to exert greater control over the net outcome than the sensitization opponent process, thereby minimizing side-effects. This conceptual model was tested by empirically validating the effectiveness of adaptation, incremental adaptation, habituation, and incremental habituation regimens to mitigate side-effects arising from exposure to an optokinetic drum. Forty college students from the University of Central Florida participated in the experimentation and were randomly assigned to a regimen. Efforts were taken to balance distribution of participants in the treatments for gender and motion sickness susceptibility. Results indicated that overall, the application of an incremental regimen is effective in reducing side-effects (e.g. malaise, dropout rates, postural instabilities, etc.) when compared to a non-incremented regimen, whether it be a one-time or repeated exposure. Furthermore, the application of the Motion History Questionnaire (MHQ) (Graybiel & Kennedy, 1965) for identifying high and low motion sickness susceptible individuals proved effective. Finally, gender differences in motion sickness were not found in this experiment as a result of balancing susceptibility with the gender subject variable. Findings from this study can be used to aid effective design of virtual environment (VE) usage regimens in an effort to manage cybersickness. Through pre-exposure identification of susceptible individuals via the MHQ, exposure protocols can be devised that may extend limits on exposure durations, mitigate side-effects, reduce dropout rates, and possibly increase training effectiveness. This document contains a fledgling set of guidelines form VE usage that append those under development by Stanney, Kennedy, & Kingdon (In press) and other previously established guidelines form simulator use (Kennedy et al., 1987). It is believed that through proper allocation of effective VE usage regimens cybersickness can be managed, if susceptible individuals are identified prior to exposure.

No / In the present study we evaluated the role of 5-HT1A receptors in mediating the inhibitory action of 8-OH-DPAT, a 5-HT1A receptor agonist, in motion sickness in Suncus murinus. 8-OH-DPAT (0.1 mg/kg, i. p) attenuated motion-induced emesis which was associated with an increase in the latency of the onset to the first emetic episode. Pre-treatment with methysergide (a 5-HT1/2/7 receptor antagonist, 1.0 mg/kg, i. p.), WAY-100635 (a 5-HT1A receptor antagonist, 1.0 mg/kg, i. p.), SB269970A (a 5-HT7 receptor antagonist, 1.0 and 5.0 mg/kg, i. p.), ondansetron (a 5-HT3 receptor antagonist, 1.0 mg/kg, i. p) or GR13808 (a 5-HT4 receptor antagonist, 0.5 mg/kg, i. p) failed to modify the inhibitory action of 8-OH-DPAT on motion sickness. Furthermore, the application of either methysergide, WAY-100635, SB269970A, ondansetron or GR13808 alone had no effect on motion sickness in its own right. These data indicate that neither 5-HT1A nor any 5-HT2 receptor subtypes, 5-HT3, 5-HT4 and 5-HT7 receptors are likely to be involved in the inhibition of motion-induced emesis mediated by 8-OH-DPAT.

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