Motion sickness in guinea pigs (Cavia porcellus) indexed by body rotation-induced conditioned taste aversions.

Ossenkopp KP, Ossenkopp MD.

Department of Psychology, University of Western Ontario, London, Canada.

The presence of motion sickness in albino guinea pigs (Cavia porcellus) was examined by using a conditioned taste aversion (CTA) as an index. Eighteen animals were divided into three groups. One group received four pairings of a novel 0.15% saccharin solution followed by 20 min of body rotation at 70 rpm (on a schedule of 15 sec on and 5 sec off). Another group received four pairings of the saccharin solution followed by exposure to sham rotation. The third group experienced the rotation procedure following access to water. The group receiving the rotation procedure contingent on presentation of the novel saccharin taste exhibited a conditioned aversion to this fluid (relative to the control groups) over days of acquisition (p less than 0.01), which subsequently dissipated when rotation was no longer contingent on the presentation of the saccharin solution (extinction). These data thus demonstrate the presence of motion sickness in guinea pigs when CTA is used as an index.

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Motion sickness susceptibility and the utilisation of visual and otolithic information for orientation.

Yardley L.

Department of Audiology, University of Southampton, UK.

Movement of large portions of the visual field can induce a static observer to experience illusory self-motion, changes in perceived orientation and motion sickness. Two experiments were performed to determine whether susceptibility to motion sickness might be related to an inability to ignore misleading visual information for orientation, measured here in terms of the magnitude of the apparent tilt of the vertical induced by rotation of the visual field about the line of sight. Significant and additive effects of sex and motion sickness susceptibility were demonstrated. Females susceptible to motion sickness proved highly inaccurate when attempting to set a line to the vertical with rotation of the background, while males resistant to motion sickness were the most accurate at this task. Two possible explanations are discussed, the first suggesting subclinical intersubject differences in otolithic sensitivity, and the second postulating deficiencies in intersensory integration. Parallels are drawn with the patterns of multisensory coordination for postural orientation seen in children and in patients with benign paroxysmal positional vertigo.

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Cerebrospinal fluid constituents of cat vary with susceptibility to motion sickness.

Lucot JB, Crampton GH, Matson WR, Gamache PH.

Department of Pharmacology, Wright State University, Dayton, OH 45435.

Six female cats, varying in susceptibility to motion sickness, were implanted with chronic cannulae in the rostral portion of the fourth ventricle. The cats were then challenged with a motion sickness-inducing stimulus. Samples of cerebrospinal fluid were withdrawn before and after emesis or 30 min of motion if emesis did not occur and again on control (no motion) days. The samples were analyzed by HPLC with an array of 16 coulometric detectors. Thirty-six compounds were identified in the samples. Baseline levels of DOPAC, MHPGSO4, uric acid, DA, 5-HIAA and HVA were lower on motion and control days in cats which became motion sick when compared with cats which did not become motion sick. None of the identified compounds varied as a function of either exposure to motion or provocation of emesis. It is concluded that susceptibility to motion sickness is a manifestation of individual differences related to fundamental neurochemical composition.

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An evaluation of cognitive-behavioral therapy for training resistance to visually-induced motion sickness.

Dobie TG, May JG, Fisher WD, Bologna NB.

Naval Biodynamics Laboratory, Michoud Station, New Orleans, LA.

This investigation examined the techniques for reducing visually-induced motion sickness. On the basis of their responses to a motion sickness history questionnaire, 32 subjects were selected and assigned to 1 of 4 groups such that the groups were matched on the basis of their ability to tolerate visually-induced apparent motion (VM). One group received 10 sessions of desensitization training only (DT); a second group received 10 sessions of cognitive therapy only (CT); a third group received 10 sessions of combined desensitization and cognitive therapy treatment (CG); and a fourth group received no treatment (C). (There are many speculations about why and how an individual's response changes with repeated stimulation. We have arbitrarily selected the term desensitization to connote the decrease in sensitivity over time with repeated exposures). The results indicated that only the groups which received cognitive therapy (i.e., CT and CG) exhibited significant increases in tolerance to VM when pretreatment measures were compared to posttreatment measures. No significant differences in pre- vs. posttreatment measures were observed in the desensitization only or control groups (i.e., DT and C). A similar pattern of results was obtained with the symptomatology data.

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[Animal model of motion sickness in rats]

[Article in Japanese]

Morita M.

Complex accelerative stimuli can induce pica in rats as well as the treatment with poisons, which means eating of non-nutritive substances such as kaolin, in proportion to the severity of their sickness. For the purpose of using pica as an index of motion sickness in rats, we examined what kind of rotation was effective for inducing pica in rats with or without normal bilateral labyrinth functions. Clinically potent anti-motion sickness drugs, such as scopolamine, methamphetamine, diphenhydramine, were examined in reducing rotation-induced pica in rats. Rats ate more kaolin after double rotation with continuously changing acceleration, than after single rotation. Both the animals treated with anti-motion sickness drugs or labyrinthectomy ate less kaolin even after double rotation. Since the physiological and pharmacological mechanisms for inducing pica in rats were similar with those of motion sickness in humans, pica in rats should be an acceptable index of their motion sickness. In order to study neural mechanisms of motion sickness in rats, we examined the effects of an anti-cholinergic as a potent anti-motion sickness drug and cholinergics as an antagonistic drug treated during the 4th-7th day of rotation on both habituation to double rotation within daily rotations for 10-11 days, using pica as an index of motion sickness. Rats were separated into three groups according to their initial susceptibility, and rats with low susceptibility were omitted in these experiments. Scopolamine (TTS-scopolamine) as an anticholinergic facilitated habituation to motion, especially in rats with moderate susceptibility. Treatment of physostigmine suppressed residual habituation to motion sickness in rats, especially with moderate susceptibility, though neostigmine, peripherally acting anti-cholinesterase, had no effect. These results suggested that centrally acting acetylcholine play an important role in suppressing habituation of motion sickness. In conclusion, rats should be a convenient model for studying for motion sickness, as we examined one of the neural mechanisms in motion sickness using pica as an index.

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Electrogastrograms during motion sickness in fasted and fed subjects.

Stewart JJ, Wood MJ, Wood CD.

Department of Pharmacology and Therapeutics, Louisiana State University Medical Center Shreveport 71130-3932.

Seven human volunteers were subjected to stressful Coriolis stimulation (rotating chair) either during the fasted state or following the ingestion of yogurt (6 oz). Subjects tested after yogurt reached a Malaise-III (M-III) endpoint of motion sickness after significantly (p less than 0.01) fewer head movements than subjects tested in the fasted state. Surface electrogastrogram (EGG) recordings at M-III were similar for both dietary states and consisted of a brief period of tachygastria, followed by a period of low amplitude EGG waves. Ingestion of yogurt enhanced susceptibility to motion sickness but did not affect the associated pattern of EGG.

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Motion sickness and gastric myoelectric activity as a function of speed of rotation of a circular vection drum.

Hu S, Stern RM, Vasey MW, Koch KL.

Department of Psychology, Pennsylvania State University, University Park 16802.

Motion sickness symptoms and electrogastrograms (EGGs) were obtained from 60 healthy subjects while they viewed an optokinetic drum rotated at one of four speeds: 15, 30, 60 or 90 degrees.s-1. All subjects experienced vection, illusory self-motion. Motion sickness symptoms increased as drum speed increased up to 60 degrees.s-1; i.e., symptoms decreased at 90 degrees.s-1. Power, spectral intensity, of the EGG at the tachygastria frequencies (4-9 cpm) was calculated at each drum rotation speed since previous studies have shown a close correspondence between development of tachygastrias and motion sickness symptoms. Power at 4-9 cpm increased as a function of drum speed up to 60 degrees.s-1 and then decreased at 90 degrees.s-1. Power at 4-9 cpm and 60 degrees.s-1 was significantly greater than at 15 degrees.s-1. The correlation between the motion sickness symptoms and the power at 4-9 cpm was significant. Thus, drum rotation speed influenced the spectral power of the EGG at 4-9 cpm, tachygastria, and the intensity of motion sickness symptoms.

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Conditioned taste aversion in humans using motion-induced sickness as the US.

Arwas S, Rolnick A, Lubow RE.

The purpose of the experiment was to demonstrate conditioned taste aversion (CTA) and latent inhibition (LI) of CTA in humans using rotation-induced motion sickness as the unconditioned stimulus. To accomplish this, flavour familiarity (familiar vs unfamiliar) and rotation (rotation vs no rotation) were manipulated in a 2 X 2 factorial design. Subjects consumed either a familiarly flavoured carbonated beverage or a novel one after which half of each group was rotated or not rotated. Two hours later the subjects were re-presented with the flavoured drink that they had previously drunk. The groups receiving rotation consumed less of the drink that the non-rotated groups, thus demonstrating CTA. The rotated group pre-exposed to the novel flavoured drink consumed less than the rotated group pre-exposed to the familiar drink, thus demonstrating LI. The effectiveness of the rotation procedure in producing motion sickness was confirmed by self-reports of general feelings and by symptom rating scales. In addition, it was found that, at the time of consuming the test drink the rotation groups' motion-sickness symptom scores were reduced to the level of the nonrotated groups. Applications of these data to the prophylactic treatment of chemotherapy-induced food aversions were discussed.

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