Motion sickness: a synthesis and evaluation of the sensory conflict theor Man Vehicle Laboratory, Massachuserrs Institute of Technology, Cambridge, MA 02139, U.S.A Received December 15. 1988 M. 1990. Motion sickness: a synthesis and evaluation of the sensory conflict theory. Can. J. Physiol. Pharmacol erebral ischemia, stimulation ofabescribing a group of common nausea syndromes originally attributed to motion- ear. Seasickness, car sickness, and ai of abdominal organ afferents, or overstimulation of the vestibular organs of the her centers mediating sickness symptoms. Unfomunately, ou Key words: motion sickness, nausea, vestibular, vision, mathematical models OMAN, C, M. 1990. Motion sickness: a synthesis and evaluation of the sensory conflict theory, Can. J. Physiol. Pharmacol. Id'auto ntes des organes abdominaux ou a 包诞m3m nt sden me. e traicsp rts s s comes ete Amun pr ceos ent e ume e. c foit sesitit he'a icom et derivant le couplage dynamique entre les signaux connlictuels putatifs et I'estime de amplitude de la nausea. D'apres ce modele, quelles devraient etre les prophets d un neurone conflictual? Traduit par la revue Until a cer Motion sickness in humans is a nausea and vomiting sy ebral blood nlow or mechanical stim ment. It is characterized by hy sical sign such bs vomiting These ideas, temed"blood and guts theones"by Reason and (1975) (ames 1882) that i and mth, and drowsiness. It has的 that motion sickness results from overstimu f abdominal afferents v that one could accurately predict whether sickness would occur (Money 1970). The physiological, behavioral, and pharmac ever,over the past 25 year Smith(1955), Money(1970), Reason and Brand(1975), Gray. researchers have concluded that thevestibular overstimul paper is to synthesize the"sensory conflict"theory for motion for the disorder, since it cannot account for several important sickness from a contemporary mathematical modelling per- facts conceming susceptibility. Among these are the fol- spective enience in a particular motion en pective, held November 12 and: 13, 19 88. the driver of a car who is in active control of his vel and has undergone the Joumal's usual peer much less susceptible to sickness than the passengers People regularly stimulate their vestibular organs vigorously
activities, Chinn(1953)and Crampton and Daunton(1983)found pr tion, almost never produce inal fluid( CSF) transport is argu ur under some conditions where the ph 卿0 ven completely absent. vomiting that is observed experime时wts al body motion stimulus is norm pathways(see below) and significant interspecies differences Just as a worki beginning to emerge, other experi ng to replicate and exten the traditional attempt ckness, even though 比二 cy n ated and cerebellar iller and Wilson 1983a hensive etiologic theory was Wilpizeski et al. 1986), and workers now doubt that medullary was an as yet unidentified signal in the orientation Certainly some aspects of the physiology of the"output" nerated or not. When this intemal neural or humoral signal been experimentally defined(e. g, Miller et al. 1987). That so atory, vasomotor, and gastric responses are consis eventually producing symptoms and signs. Many worke tent signs of motion sickness indicates that areas in the reticu- undoubtedly assumed that the linkage would be easily identi- lar core of the brainstem traditionally associated with of spatial orientation and emetic pathways in the CNS were animals and people can be made motion sick, the limt better understood ortex (HPA)neuroend Physiological basis of motion sickness normally involved in mediating responses: increases in circu- nd during sick nat effective drugs stem that subserve postural simply raise the threshold for sickness. Antimotion sicknes now known to by Henn ( 1980). A brainstem 1954), which has been found to receive convergent inputs from a variety of other central and peripheral sources, includ- of th w油AM由如 not yet have: complete physiologi ctivity in this vomiting center(Money 1970). The integrity of definition of motion sickness, the development of a succession both the vomiting center and an adjacent"chem receptive of"sensory r etiologic perspective on the syndrome. The the fourth ventricle, was found to conflict theory has been widely accepted, and as a result 4: Brizzee and Neal 1954). abla- ts indicated the cerebellar nodulus and uvul tacle scones, wide-screen movie sickness, figh sta. spor somei the orientation brain ness), and the nausea and the vomiting produced by vestibu probably via the cerebellum, to the chemoreceptive trigg nd-organ disease simply as different examples of a zone, which in tum activated the vomiting center. wang and sensory conflict"related nausea and vomiting syndrom
AN, J. PHYSIOL. PHARMACOL. VOL: 68. 1990 Claremont(1931)observed that motion sickness symptoms ry input. These fetched traces. I to we regard as normal. This normality is dis- specific stimulus for motion sickness, a"neural mismatch board ship. Our eyes here tell us that entation e we are sory conflict signals, Reason noted that any stimulus situa oving. This basi nat until recently, statements of the conflict theory did not hypothesized to involve updating of the neural store with new and The Imptions are needed. Thus, these statements of the model was only qual ot themselves represent complete con- in additional difficulty was that the essential idea("sensory intuitively defined. The model did not really address the ques- An conflict")was at first only loosely defined. In early statemen signal, other make one sick, or what functi sigmal provided by different sensory d anal-otolith"and"visual-inertial"conflicts). focussed only on sensory connie ynamic elements and did not incorpora Pmmm联: must be present to account for the latency and peculiar time hich owever,in 1978, this definition underwent a major revision: course of symptoms Reason(1978)noted that in terms of the actual pson of affer- in the CNS, a direct inte matical definition of al, quantitative"as if'mathematical models namic response and coding type), and proven to be useful tools for scientific investigation, beca hether they can be said to"conflict""or not actually depends n coding, context, and previous sensory-motor expenence y compel eme to imore concise i des sibe the nim tor sce models are primarily heuristic, the intellectual process often and is today probably the best known, of a newer group of To address some of the deficiencies eories sometimes collectively referred to as"sensory mismatch"formulation, the present author (Oman 1978 82 ariants of the older"intermodality cor theory ve. The model incorporated and extended Reason's hypothe reviews sometimes casu- sis and containe tions even when a formally compl Rm邮mm如60m图mbm drew on the well known"reafference eriments and models of actively sory signals for consistency by computin the componed of manua contro (Bare and k lineman i f in mh tel 0 Borah et al. 1978). The latter have be d to not defined in the same sense as that used by th the cal environment. As a body movement is com Reason and manded, the CNS is assumed to fetch from the neural store the In the design of guidance, control, and navigation systems
