Therefore, CAHI may be able to diminish the hypothesized fluid shift to the CNS and inner ear under the fluid shift theory. Carbonic anhydrase inhibitors (CAHI) are known to suppress active production of CSF and may be able to inhibit production of perilymph in the semi-circular canals. "sensory conflict theory" hypothesizes that unfamiliar accelerational and gravitational inputs from the middle ear conflict with visual inputs and lead to SMS. The "fluid shift theory" pre-supposes an active or passive shift of body fluid to the central nervous system (CNS) and vestibulo-auditory mechanisms. Two theories that have been advanced to explain SMS are the "fluid shift theory" and the "vestibulo-ocular sensory conflict theory". Space motion sickness (SMS) is an important medical problem facing NASA's space shuttle program. Although the effectiveness of the shutter glasses as a countermeasure for motion sickness is not implied by this test, the results did indicated that shutter glasses, particularly the 8 Hz device demonstrated promise and should be explored as a non-pharmacological motion sickness prevention strategy. The testing was deliberately limited with no intentions of drawing firm conclusions as to the shutter glasses' efficacy. This preliminary testing of the shutter glasses was conducted to determine their worthiness of further study. Following each flight, each participant filled out a motion sickness questionnaire and provided subjective feedback. flights in the cabin of a Black Hawk helicopter: the first flight with shutter glasses and the second without them. The purpose was to examine the mission applicability and product potential of the glasses and to gain support for their inclusion in future USAARL motion sickness studies. This report presents the results of preliminary tests conducted by the USAARL of two sets of stroboscopic shutter glasses (at 4Hz and 8 Hz) proposed as a countermeasure for motion sickness. Therefore, the vestibular system plays a critical role for neural representations of spatial aspects of bodily self-consciousness. We propose that vestibular processing in these cortical regions is critical in linking multisensory signals from the body (personal and peripersonal space) with external (extrapersonal) space. Finally, we discuss the role for four posterior brain regions that process vestibular and other multisensory signals to encode spatial aspects of bodily self-consciousness: temporoparietal junction, parietoinsular vestibular cortex, ventral intraparietal region, and medial superior temporal region. We compare these findings to data showing vestibular effects on mental spatial transformation, self-motion perception, and body representation showing vestibular contributions to various spatial representations of the body with respect to the external world. We review here recent data showing vestibular effects on first-person perspective (the feeling from where "I" experience the world) and self-location (the feeling where "I" am located in space). Because the vestibular system encodes head position and movement in three-dimensional space, vestibular cortical processing likely contributes to spatial aspects of bodily self-consciousness. Self-consciousness is typically bound to a body, and particularly to the spatial dimensions of the body, as well as to its location and displacement in the gravitational field. Self-consciousness is the remarkable human experience of being a subject: the "I".
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