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Robert M. Stern - One of the best experts on this subject based on the ideXlab platform.
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Enhanced perceptions of control and predictability reduce motion-induced nausea and gastric dysrhythmia
Experimental Brain Research, 2014Co-Authors: Max E. Levine, Robert M. Stern, Kenneth L KochAbstract:Nausea is a debilitating condition that is typically accompanied by gastric dysrhythmia. The enhancement of perceived control and predictability has generally been found to attenuate the physiological stress response. The aim of the present study was to test the effect of these psychosocial variables in the context of nausea, motion sickness, and gastric dysrhythmia. A 2x2, independent-groups, factorial design was employed in which perceived control and predictability were each provided at high or low levels to 80 participants before exposure to a rotating Optokinetic Drum. Ratings of nausea were obtained throughout a 6-min baseline period and a 16-min Drum rotation period. Noninvasive recordings of the electrical activity of the stomach called electrogastrograms were also obtained throughout the study. Nausea scores were significantly lower among participants with high control than among those with low control, and were significantly lower among participants with high predictability than among those with low predictability. Estimates of gastric dysrhythmia obtained from the EGG during Drum rotation were significantly lower among participants with high predictability than among those with low predictability. A significant interaction effect of control and predictability on gastric dysrhythmia was also observed, such that high control was only effective for arresting the development of gastric dysrhythmia when high predictability was also available. Stronger perceptions of control and predictability may temper the development of nausea and gastric dysrhythmia during exposure to provocative motion. Psychosocial interventions in a variety of nausea contexts may represent an alternative means of symptom control.
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Susceptibility to nausea and motion sickness as a function of the menstrual cycle.
Women's health issues : official publication of the Jacobs Institute of Women's Health, 2008Co-Authors: Robert L. Matchock, Max E. Levine, Peter J. Gianaros, Robert M. SternAbstract:Purpose The present study examined whether susceptibility to nausea and other symptoms of vection-induced motion sickness vary as a function of phase of the menstrual cycle, as research findings in this area are sparse and contradictory. Design Ninety young women (42 current users of oral contraceptives) were exposed to a rotating Optokinetic Drum during the peri-menses or peri-ovulatory phase of the menstrual cycle in an independent-groups, quasi-experimental design. Nausea and motion sickness symptoms were assessed using the Nausea Profile (NP) and the Subjective Symptoms of Motion Sickness (SSMS) questionnaire. Results Among women not on oral contraceptives, reports of nausea and motion sickness by women in the peri-menses phase were more severe than reports by women in the peri-ovulatory phase. By contrast, among women taking oral contraceptives, reports of nausea and motion sickness did not differ by the same categorical phase of the menstrual cycle. Conclusions We speculate that fluctuating estrogen levels over the course of the menstrual cycle may influence the experience of or susceptibility to nausea and motion sickness during illusory self-motion and other nauseogenic contexts.
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Relationship between temporal changes in cardiac parasympathetic activity and motion sickness severity
Psychophysiology, 2003Co-Authors: Peter J. Gianaros, Eric R. Muth, Karen S. Quigley, Max E. Levine, Raymond C. Vasko, Robert M. SternAbstract:Chemotherapy-induced nausea has been associated with a time-related decrease in cardiac parasympathetic activity. We tested the hypothesis that a time-related decrease in cardiac parasympathetic activity would also be associated with nausea and other motion sickness symptoms during illusory self-motion (vection). Fifty-nine participants (aged 18-34 years: 25 male) were exposed to a rotating Optokinetic Drum to induce vection. Symptoms of motion sickness and an estimate of cardiac parasympathetic activity (respiratory sinus arrhythmia; RSA) were obtained at baseline and throughout a Drum-rotation period. As expected, motion sickness symptoms increased and RSA decreased over time during Drum rotation. Moreover, greater decreases in RSA over time correlated with greater motion sickness severity. These results suggest that a time-related decrease in cardiac parasympathetic activity may be an important correlate of nausea and motion sickness across different evocative contexts.
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Acupressure relieves the symptoms of motion sickness and reduces abnormal gastric activity.
Alternative therapies in health and medicine, 2001Co-Authors: Robert M. Stern, Eric R. Muth, Jokerst, Hollis CAbstract:Context Acupuncture at the P6 or Neiguan point to treat nausea and vomiting has been practiced in China for many years. More recently, acupressure at P6 has been used successfully to decrease the symptoms of pregnancy sickness and with mixed results to decrease motion sickness. Objective To determine whether an Acuband, a commercially available acupressure wristband, would relieve the symptoms of motion sickness. Method 25 healthy subjects, aged 18 to 22 years, prescreened for susceptibility to motion sickness, were tested on 3 separate occasions in a rotating Optokinetic Drum with the following conditions: wearing an Acuband on the wrist, wearing an Acuband on the arm, and wearing no Acuband. Main outcome measures Subjective symptoms of motion sickness and abnormal gastric activity, as recorded via electrogastrography, were obtained throughout the procedure. Results Subjects reported significantly fewer symptoms of motion sickness on days when wearing the Acuband on the wrist or the arm than they did on control days (when they wore no Acuband). Subjects also showed less abnormal gastric activity on the days when wearing an Acuband than they did on control days. Conclusion An Acuband worn on the wrist or forearm decreases the symptoms of motion sickness and the gastric activity that usually accompanies motion sickness.
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Gastric myoelectrical and autonomic cardiac reactivity to laboratory stressors.
Psychophysiology, 2001Co-Authors: Peter J. Gianaros, Karen S. Quigley, J. Toby Mordkoff, Robert M. SternAbstract:We evaluated the effects of two laboratory stressors (speech preparation and isometric handgrip) on gastric myoelectrical and autonomic cardiac activity, and the extent to which autonomic responses to these stressors and somatization predict reports of motion sickness during exposure to a rotating Optokinetic Drum. Both stressors prompted a decrease in preejection period (PEP) and respiratory sinus arrhythmia (RSA), and an increase in a dysrhythmic pattern of gastric myoelectrical activity, termed gastric tachyarrhythmia. Stressor-induced decreases in RSA and higher somatization scores predicted increased reports of motion sickness during Drum rotation. These results demonstrate that laboratory stressors concurrently affect gastric myoelectrical activity and autonomic control of the heart, and that stressor-induced decreases in RSA and higher levels of somatization predict motion sickness susceptibility.
Kenneth L Koch - One of the best experts on this subject based on the ideXlab platform.
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Enhanced perceptions of control and predictability reduce motion-induced nausea and gastric dysrhythmia
Experimental Brain Research, 2014Co-Authors: Max E. Levine, Robert M. Stern, Kenneth L KochAbstract:Nausea is a debilitating condition that is typically accompanied by gastric dysrhythmia. The enhancement of perceived control and predictability has generally been found to attenuate the physiological stress response. The aim of the present study was to test the effect of these psychosocial variables in the context of nausea, motion sickness, and gastric dysrhythmia. A 2x2, independent-groups, factorial design was employed in which perceived control and predictability were each provided at high or low levels to 80 participants before exposure to a rotating Optokinetic Drum. Ratings of nausea were obtained throughout a 6-min baseline period and a 16-min Drum rotation period. Noninvasive recordings of the electrical activity of the stomach called electrogastrograms were also obtained throughout the study. Nausea scores were significantly lower among participants with high control than among those with low control, and were significantly lower among participants with high predictability than among those with low predictability. Estimates of gastric dysrhythmia obtained from the EGG during Drum rotation were significantly lower among participants with high predictability than among those with low predictability. A significant interaction effect of control and predictability on gastric dysrhythmia was also observed, such that high control was only effective for arresting the development of gastric dysrhythmia when high predictability was also available. Stronger perceptions of control and predictability may temper the development of nausea and gastric dysrhythmia during exposure to provocative motion. Psychosocial interventions in a variety of nausea contexts may represent an alternative means of symptom control.
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Effects of vection-induced motion sickness on gastric myoelectric activity and oral-cecal transit time
Digestive Diseases and Sciences, 1996Co-Authors: Eric R. Muth, Robert M. Stern, Kenneth L KochAbstract:The purpose of this study was to investigate the effects of vection-induced motion sickness on three cycle per minute gastric myoelectric activity and oral-cecal transit time. Forty-five subjects were exposed to a rotating Optokinetic Drum while electrogastrograms and subjective reports of symptoms were monitored. Prior to exposure, baseline breath hydrogen levels were established and subjects ingested vanilla pudding containing 10 g of lactulose. Breath hydrogen measurements were obtained before Drum rotation and every 10 minutes after rotation, for 3 hr. Based on the severity of motion sickness symptoms reported, subjects were divided into two groups: a group susceptible to, and a group not susceptible to, vection-induced motion sickness. Averaged across subjects, the percentage of three cycle per minute activity decreased from baseline to rotation (3.6%) and from rotation to recovery (3.0%) [ F (2/70)=2.43, P
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Asian Hypersusceptibility to Motion Sickness
Human heredity, 1996Co-Authors: Robert M. Stern, Sebastian Uijtdehaage, Eric R. Muth, Kenneth L KochAbstract:A rotating Optokinetic Drum was used in three laboratory studies to test the hypothesis that Asian subjects are hypersusceptible to motion sickness. The results of the first study showed that Chinese women compared to European-American and African-American women experienced significantly more severe symptoms of motion sickness and greater disturbance of normal gastric myoelectric activity. A second study yielded similar results using American-born children of Asian parents. The results of a third study using Chinese men and women were similar and showed a significant increase in vasopressin during rotation. Possible genetic mechanisms that may account for these results are discussed.
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Assessment of the multiple dimensions of nausea: The Nausea Profile (NP)
Journal of psychosomatic research, 1996Co-Authors: Eric R. Muth, Robert M. Stern, Julian F. Thayer, Kenneth L KochAbstract:Nausea, unlike emesis, is a subjective experience that is difficult to describe to others, be they clinicians or researchers. Previous research has been limited to examining the frequency, severity, and duration of nausea. The goal of this study was to design a questionnaire that would allow for the evaluation of the characteristics of nausea across individuals and situations. This study consisted of 4 stages: descriptors were generated, categorized into 3 dimensions, and reevaluated to verify their reliability; in the final stage, the developed checklist was compared to a visual-analogue-scale (VAS) report of nausea in subjects exposed to a rotating Optokinetic Drum to stimulate nausea. The overall nausea checklist score and the VAS score were highly correlated (r = 0.71, p < 0.01). The development and use of the nausea checklist are discussed.
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Effects of phenytoin on vection-induced motion sickness and gastric myoelectric activity.
Aviation space and environmental medicine, 1994Co-Authors: Robert M. Stern, Sebastian Uijtdehaage, Eric R. Muth, Kenneth L KochAbstract:The purpose of this study was to test the prophylactic effects of a single low dose of phenytoin on motion sickness. In this double-blind study, fasted male subjects who were susceptible to motion sickness were given either a 200-mg tablet of phenytoin (N = 19) or a placebo (N = 16). Electrogastrograms (EGG's) were recorded predrug, postdrug (4 h after ingestion of drug), before Drum rotation, and during Drum rotation. During testing, subjects were exposed to an Optokinetic Drum which was stationary for 8 min and which then rotated at 10 rpm for 16 min. The results showed that the phenytoin subjects had a lower mean subjective symptom score than the placebo group (5.8 vs. 7.1), but the difference was not significant. However, 6 of 16 placebo subjects requested early termination of Drum rotation due to symptom severity, whereas only 2 of 19 phenytoin subjects terminated testing prematurely (X2 = 3.89, p < 0.05). The phenytoin group showed no increase in gastric tachyarrhythmia, the pattern of gastric myoelectric activity that usually accompanies nausea, during Drum rotation, whereas tachyarrhythmia doubled for the placebo group. In conclusion, we have demonstrated that a single low dose of phenytoin prevents the development of gastric tachyarrhythmia and decreases the intensity of motion sickness symptoms.
Eric R. Muth - One of the best experts on this subject based on the ideXlab platform.
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Protein-predominant meals inhibit the development of gastric tachyarrhythmia, nausea and the symptoms of motion sickness
Alimentary pharmacology & therapeutics, 2004Co-Authors: Max E. Levine, Eric R. Muth, Manda J. Williamson, R. M. SternAbstract:SUMMARY Background: Meal ingestion has been suggested to reduce susceptibility to the development of gastric tachyarrhythmia, the abnormal activity of the stomach that frequently accompanies nausea. Aim: To determine the types of meal that are most effective in preventing the development of gastric tachyarrhythmia, nausea and the symptoms of motion sickness provoked by a rotating Optokinetic Drum. Method: Participants received a carbohydrate beverage, a protein-predominant beverage or nothing immediately before exposure to the rotating Drum. Subjective symptoms of motion sickness and electrogastrograms were collected during a 6-min baseline period and a subsequent 16-min Drum rotation period. Results: Subjective symptoms of motion sickness scores were significantly more severe during the nomeal condition than during either the protein or carbohydrate condition. Central, peripheral and, to some extent, gastrointestinal symptoms were more severe during the carbohydrate condition than during the protein condition. Gastric tachyarrhythmia increased significantly less from baseline to Drum rotation during both the protein and carbohydrate conditions than during the no-meal condition. Conclusions: Liquid protein-predominant meals were most effective in suppressing both the development of gastric tachyarrhythmia and the entire spectrum of motion sickness symptoms, including nausea.
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Relationship between temporal changes in cardiac parasympathetic activity and motion sickness severity
Psychophysiology, 2003Co-Authors: Peter J. Gianaros, Eric R. Muth, Karen S. Quigley, Max E. Levine, Raymond C. Vasko, Robert M. SternAbstract:Chemotherapy-induced nausea has been associated with a time-related decrease in cardiac parasympathetic activity. We tested the hypothesis that a time-related decrease in cardiac parasympathetic activity would also be associated with nausea and other motion sickness symptoms during illusory self-motion (vection). Fifty-nine participants (aged 18-34 years: 25 male) were exposed to a rotating Optokinetic Drum to induce vection. Symptoms of motion sickness and an estimate of cardiac parasympathetic activity (respiratory sinus arrhythmia; RSA) were obtained at baseline and throughout a Drum-rotation period. As expected, motion sickness symptoms increased and RSA decreased over time during Drum rotation. Moreover, greater decreases in RSA over time correlated with greater motion sickness severity. These results suggest that a time-related decrease in cardiac parasympathetic activity may be an important correlate of nausea and motion sickness across different evocative contexts.
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Acupressure relieves the symptoms of motion sickness and reduces abnormal gastric activity.
Alternative therapies in health and medicine, 2001Co-Authors: Robert M. Stern, Eric R. Muth, Jokerst, Hollis CAbstract:Context Acupuncture at the P6 or Neiguan point to treat nausea and vomiting has been practiced in China for many years. More recently, acupressure at P6 has been used successfully to decrease the symptoms of pregnancy sickness and with mixed results to decrease motion sickness. Objective To determine whether an Acuband, a commercially available acupressure wristband, would relieve the symptoms of motion sickness. Method 25 healthy subjects, aged 18 to 22 years, prescreened for susceptibility to motion sickness, were tested on 3 separate occasions in a rotating Optokinetic Drum with the following conditions: wearing an Acuband on the wrist, wearing an Acuband on the arm, and wearing no Acuband. Main outcome measures Subjective symptoms of motion sickness and abnormal gastric activity, as recorded via electrogastrography, were obtained throughout the procedure. Results Subjects reported significantly fewer symptoms of motion sickness on days when wearing the Acuband on the wrist or the arm than they did on control days (when they wore no Acuband). Subjects also showed less abnormal gastric activity on the days when wearing an Acuband than they did on control days. Conclusion An Acuband worn on the wrist or forearm decreases the symptoms of motion sickness and the gastric activity that usually accompanies motion sickness.
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The effect of autonomic nervous system activity on gastric myoelectrical activity: does the spectral reserve hypothesis hold for the stomach?
Biological psychology, 1998Co-Authors: Eric R. Muth, Robert M. Stern, Julian F. Thayer, Bruce H. Friedman, Christopher L. DrakeAbstract:Previous studies have associated changes in gastric myoelectrical activity during motion sickness, as indexed using the electrogastrogram (EGG), with changes in autonomic nervous system (ANS) activity. Subjects who did not report nausea in a rotating Optokinetic Drum were characterized by normal 3 cycles per minute (cpm) gastric myoelectrical activity, strong parasympathetic nervous system (PNS) activity, and low sympathetic nervous system (SNS) activity. The goals of this study were: (1) to determine whether tasks previously shown to alter ANS activity as indexed by changes in cardiac inter-beat intervals (IBIs) would result in systematic changes in gastric myoelectrical activity in accord with the findings from motion sickness studies; and (2) to determine whether the 'spectral reserve hypothesis' applies to gastric myoelectrical activity. EGGs and IBIs were collected from 24 healthy subjects during resting/baseline, reaction time/shock-avoidance (RT) and cold face stress (CF) tasks. Tachyarrhythmia was found to be significantly greater during the RT task than during the baseline and CF tasks. It was concluded that: (1) tasks that alter ANS activity do systematically alter gastric myoelectrical activity; and (2) gastric myoelectrical activity does not follow the cardiac model of health being associated with increased spectral complexity.
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Effects of vection-induced motion sickness on gastric myoelectric activity and oral-cecal transit time
Digestive Diseases and Sciences, 1996Co-Authors: Eric R. Muth, Robert M. Stern, Kenneth L KochAbstract:The purpose of this study was to investigate the effects of vection-induced motion sickness on three cycle per minute gastric myoelectric activity and oral-cecal transit time. Forty-five subjects were exposed to a rotating Optokinetic Drum while electrogastrograms and subjective reports of symptoms were monitored. Prior to exposure, baseline breath hydrogen levels were established and subjects ingested vanilla pudding containing 10 g of lactulose. Breath hydrogen measurements were obtained before Drum rotation and every 10 minutes after rotation, for 3 hr. Based on the severity of motion sickness symptoms reported, subjects were divided into two groups: a group susceptible to, and a group not susceptible to, vection-induced motion sickness. Averaged across subjects, the percentage of three cycle per minute activity decreased from baseline to rotation (3.6%) and from rotation to recovery (3.0%) [ F (2/70)=2.43, P
Frederick Bonato - One of the best experts on this subject based on the ideXlab platform.
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a wearable device providing a visual fixation point for the alleviation of motion sickness symptoms
Military Medicine, 2015Co-Authors: Frederick Bonato, Andrea Bubka, Wesley Wo KruegerAbstract:ABSTRACT Objectives: Motion sickness (MS) can be problematic for many military operations. Some pharmaceutical countermeasures are effective but can lead to side effects. Non-pharmaceutical countermeasures vary in effectiveness and can require time to be beneficial (e.g., desensitization). Previous research suggests that visual fixation can alleviate MS symptoms. In the current experiment we tested the effectiveness of a user-worn device that provides a visual fixation point that moves with the user. Methods: Fourteen subjects viewed the interior of a rotating Optokinetic Drum (60°/s) through a visor that displayed either a clear view of the scene (control) or the scene with a fixation point (experimental). After 5 minutes of viewing, symptoms were assessed using (1) the Simulator Sickness Questionnaire that yields four scores (total, nausea, oculomotor, and disorientation) and (2) a 0 to 10 MS overall scale. Results: Viewing the fixation point resulted in significantly lower scores for all measures. Cont...
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Visual blur and motion sickness in an Optokinetic Drum.
Aerospace medicine and human performance, 2015Co-Authors: Frederick Bonato, Andrea Bubka, William ThorntonAbstract:BACKGROUND: The most commonly cited hypotheses for motion sickness (MS) focus on inconsistent sensory inputs. Visual/vestibular conflicts may lead to MS, but visual input from retinal regions/neural pathways that are sensitive to motion might bear more weight in MS etiology. We hypothesized that inducing blurred vision in an Optokinetic Drum would attenuate the influence of foveal (parvocellular) input, but not peripheral (magnocellular) input that is sensitive to motion. Increased relative influence of peripheral visual input was predicted to subsequently lead to more visual/vestibular conflict and subsequently more severe MS symptoms. METHODS: Through goggles that were either clear or frosted, 15 subjects (5 men, 10 women, mean age = 24.9 yr, range = 18-49) viewed the interior of a rotating (60° · s(-1)) Optokinetic Drum for 10 min. Subjects completed the Simulator Sickness Questionnaire (SSQ) before and after viewing. Overall subjective sickness ratings (0-10) and visually induced self-motion perception (vection) ratings (0-10) were also recorded. RESULTS: Postexposure SSQ scores obtained in the blur condition (total - 52.9, oculomotor - 38.9, disorientation - 69.6) were significantly higher than those obtained in the control condition (total - 30.4, oculomotor - 21.7, disorientation - 37.8). Overall sickness ratings and vection ratings were also significantly higher in the blur condition. CONCLUSIONS: These results suggest that visual blur can exacerbate MS, perhaps because of differential influences of visual pathways. Although these results were obtained with an Optokinetic Drum, possible effects of visual blurring in motion provocative environments such aircraft, watercraft, spacecraft, and land vehicles should be considered.
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Rotation velocity change and motion sickness in an Optokinetic Drum.
Aviation space and environmental medicine, 2006Co-Authors: Andrea Bubka, Frederick Bonato, Scottie Urmey, Dawn MycewiczAbstract:Background: Stationary subjects who view the interior of an Optokinetic Drum often experience motion sickness (MS) symptoms, perhaps because visual and vestibular sensory inputs are in conflict. It was predicted that intermittently changing Drum rotation velocity would cause an increase in sensory conflict, and subsequently lead to more MS. Visual input indicating frequent changes in self-motion would not be consistent with vestibular input indicating no self-motion. When Drum rotation is steady, visual and vestibular inputs are more likely to agree given that the vestibular organs only respond to change. Methods: There were 12 individuals who participated in the experiment (7 men, 5 women, mean age = 24.0 yr). In two conditions subjects viewed the interior of an Optokinetic Drum that steadily rotated at either 5 RPM or 10 RPM. In a third condition Drum velocity alternated every 30 s between 5 RPM and 10 RPM (5/10 RPM condition). In all conditions the subject's head was immobilized in the center of the Drum that rotated on an Earth-vertical axis. Subjects completed the Simulator Sickness Questionnaire (SSQ) designed by Kennedy and colleagues both before a trial and after 4 min of Drum viewing. A total SSQ score and three SSQ sub-scores (nausea, oculomotor, and disorientation) were obtained. Results: Mean post-treatment total SSQ scores (mean = 41) were significantly the highest in the 5/10 RPM condition followed by the conditions of steady rotation velocity at 10 RPM (mean = 36) and 5 RPM (mean = 24). Likewise, mean nausea sub-scores were also the highest (mean = 24) in the 5/10 RPM condition followed by the 10 RPM condition (mean = 19) and the 5 RPM condition (mean = 11). Conclusions: These results support the hypothesis that a conflict between sensed and expected effects of self-motion alone can lead to MS. Changing rotation velocity increases sensory conflict that in turn leads to more MS.
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Chromaticity, spatial complexity, and self-motion perception.
Perception, 2006Co-Authors: Frederick Bonato, Andrea BubkaAbstract:The effects of visual field color and spatial complexity on self-motion perception were investigated by placing observers inside a large rotating cylinder (Optokinetic Drum). Under Optokinetic-Drum conditions visually induced self-motion (vection) is typically perceived within 30 s, even though all forms of sensory input (eg vestibular, proprioceptive, auditory), except vision, indicate that the observer is stationary. It was hypothesized that vection would be hastened and vection magnitude increased by adding chromatic colors and spatial complexity to the lining of an Optokinetic Drum. Addition of these visual-field characteristics results in an array that shares more visual-field characteristics with our typical environment that usually serves as a stable frame of reference regarding self-motion perception. In the color experiment, participants viewed vertical stripes that were: (i) black and white, (ii) various gray shades, or (iii) chromatic. In the spatial complexity experiment, participants were presented with: (i) black-and-white vertical stripes, or (ii) a black-and-white checkerboard pattern. Drum rotation velocity was 5 rev. min(-1) (30 degrees s(-1)), and both vection onset and magnitude were measured for 60 s trials. Results indicate that chromaticity and spatial complexity hasten the onset of vection and increase its perceived magnitude. Chromaticity and spatial complexity are common characteristics of the environments in which our visual system evolved. The presence of these visual-field features in an optic flow pattern may be treated as an indicator that the scene being viewed is stationary and that the observer is moving.
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Rotation direction change hastens motion sickness onset in an Optokinetic Drum.
Aviation space and environmental medicine, 2005Co-Authors: Frederick Bonato, Andrea Bubka, Meredith L. StoryAbstract:BACKGROUND Many stationary subjects who view the patterned interior of a rotating cylinder (Optokinetic Drum) experience motion sickness (MS) symptoms. An experiment was conducted to investigate the effects of rotation direction change on MS onset and severity. It was predicted that intermittently changing rotation direction would hasten MS onset due to an increased degree of visual/vestibular sensory conflict. METHODS There were 12 individuals who participated in the experiment (4 men, 8 women, mean age = 24.4 yr). Subjects viewed the interior of an Optokinetic Drum that rotated at 5 rpm (30 degrees x s(-1)). Drum rotation was either consistently in the same direction or rotation direction changed every 30 s. Eight MS symptoms were assessed at 2-min intervals using a subjective scale (0 = none, 1 = slight, 2 = moderate, 3 = severe). RESULTS Overall, MS onset was fastest when Drum rotation direction changed. Specific MS symptoms significantly affected were dizziness, stomach awareness, and nausea. CONCLUSIONS These results suggest that a lack of correlation between the sensed and expected effects of motion alone can lead to MS. These results cannot be accounted for by a lack of correlation between sensed and expected gravitational vertical given that these were held constant across conditions.
S. M. Highstein - One of the best experts on this subject based on the ideXlab platform.
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Dorsal Y group in the squirrel monkey. I. Neuronal responses during rapid and long-term modifications of the vertical VOR.
Journal of neurophysiology, 1995Co-Authors: A. M. Partsalis, Yihong Zhang, S. M. HighsteinAbstract:1. The activity of 113 Y group neurons was recorded extracellularly in 5 alert squirrel monkeys. Sixty-two cells were recorded in naive animals, and 51 cells were recorded after adaptation of the vestibuloocular reflex (VOR) with the use of telescopic lenses. The animals were lying on their right side, so that head rotation was in the vertical (pitch) plane and Optokinetic stimulation elicited vertical eye movement. The responses of most cells, as well as the concurrent eye movement, were studied during 1) the VOR, elicited in darkness or in light by sinusoidal head rotation, 2) visual following, elicited by sinusoidal rotation of a full-field Optokinetic Drum around the stationary animal, and 3) paradigms of visual-vestibular interaction, elicited by combined sinusoidal vestibular and Optokinetic stimulation. Stimulation parameters for both head and Drum velocity were usually 0.5 Hz, 35 degrees/s peak velocity. 2. Y group cells respond vigorously during visual following and during suppression of the VOR (produced by in-phase rotation of the head and the Optokinetic Drum); the response is approximately in-phase with eye velocity during visual following, and approximately in-phase with head velocity during suppression of the VOR. During the VOR in darkness, Y cells usually exhibit only slight modulation. The results suggest a linear interaction of visual following and vestibular signals on Y cells during vertical visual-vestibular interaction. Taking into account the excitatory projection of Y cells to superior rectus and inferior oblique motoneurons, a causal role of the Y group in rapid modification of VOR gain during visual-vestibular interaction is suggested. 3. Nine Y neurons from two animals were recorded continuously, for periods ranging from 30 min to 5 h, while the VOR was being adapted to higher or lower gain. Progressive changes of the gain of the VOR in darkness were evident after approximately 30 min from the initiation of head rotation under visual-vestibular mismatch. Consistent changes of the gain and/or phase of the neuronal response during the VOR in darkness were noted in all cases. The phase of the neuronal response gradually approximated head velocity phase during adaptation of the VOR to low gain, increases in the neuronal gain thereafter ensued; the opposite changes were observed during adaptation of the VOR to high gain. 4. Sixteen Y cells were recorded from 1 animal chronically adapted to high VOR gain with the use of magnifying lenses, and 35 cells were recorded from 2 animals chronically adapted to low VOR gain with the use of miniaturizing lenses.(ABSTRACT TRUNCATED AT 400 WORDS)