2004 年 63 巻 2 号 p. 67-80
Various factors are involved in the onset of motion sickness. As an investigation of one of those factors, the spatial orientation of experimental subjects was changed, and the relationship to the development of motion sickness was examined. For an objective study, it is necessary to establish an experimental model of motion sickness. Accordingly, artificial visual field information was created, and a computer capable of highspeed calculation was used to stimulate the experimental subjects with images undergoing temporal or spatial changes. Individual experimental subjects showed considerable variation in the development of motion sickness. Thus, it was important to perform the experiments on highly susceptible subjects. The results showed that, when for both time and space, the phase was asynchronized, motion sickness manifested at a high incidence. At the time motion sickness is manifested, there is always abnormal secretion of hypothalamus-pituitary-adrenal axis hormones and the development of symptoms of autonomic nervous system instability. For this reason, it can be surmised that there is involvement of emotions and the autonomic nervous system as a result of changes in spatial orientation. It can be thought that this is due to a state of asynchronization of the intrinsic information that leads to motor commands. In particular, information from an intrinsic model with unanticipated asynchronization of eye movement and head movement is important. The relationships among spatial orientation, head-eye movement, the memory process and emotion in the manifestation of motion sickness is discussed.