Perception of the Body in Space: Mechanisms

The principal topic is the perception of body orientation and motion in space and the extent to which these perceptual abstraction can be related directly to the knowledge of sensory mechanisms, particularly for the vestibular apparatus. Spatial orientation is firmly based on the underlying sensory mechanisms and their central integration. For some of the simplest situations, like rotation about a vertical axis in darkness, the dynamic response of the semicircular canals furnishes almost enough information to explain the sensations of turning and stopping. For more complex conditions involving multiple sensory systems and possible conflicts among their messages, a mechanistic response requires significant speculative assumptions. The models that exist for multisensory spatial orientation are still largely of the non-rational parameter variety. They are capable of predicting relationships among input motions and output perceptions of motion, but they involve computational functions that do not now and perhaps never will have their counterpart in central nervous system machinery. The challenge continues to be in the iterative process of testing models by experiment, correcting them where necessary, and testing them again

Habituation to novel visual vestibular environments with special reference to space flight

The etiology of space motion sickness and the underlying physiological mechanisms associated with spatial orientation in a space environment were investigated. Human psychophysical experiments were used as the basis for the research concerning the interaction of visual and vestibular cues in the development of motion sickness. Particular emphasis is placed on the conflict theory in terms of explaining these interactions. Research on the plasticity of the vestibulo-ocular reflex is discussed

I Am The Passenger: How Visual Motion Cues Can Influence Sickness For In-Car VR

This paper explores the use of VR Head Mounted Displays (HMDs) in-car and in-motion for the first time. Immersive HMDs are becoming everyday consumer items and, as they offer new possibilities for entertainment and productivity, people will want to use them during travel in, for example, autonomous cars. However, their use is confounded by motion sickness caused in-part by the restricted visual perception of motion conflicting with physically perceived vehicle motion (accelerations/rotations detected by the vestibular system). Whilst VR HMDs restrict visual perception of motion, they could also render it virtually, potentially alleviating sensory conflict. To study this problem, we conducted the first on-road and in motion study to systematically investigate the effects of various visual presentations of the real-world motion of a car on the sickness and immersion of VR HMD wearing passengers. We established new baselines for VR in-car motion sickness, and found that there is no one best presentation with respect to balancing sickness and immersion. Instead, user preferences suggest different solutions are required for differently susceptible users to provide usable VR in-car. This work provides formative insights for VR designers and an entry point for further research into enabling use of VR HMDs, and the rich experiences they offer, when travelling

Research on habituation to novel visual-vestibular environments with particular reference to space flight

Progress in the development of a cohesive theory of the underlying physiological mechanisms associated with spatial orientation in unusual environments is described. Results can be applied to providing means of preventing and/or minimizing the space motion sickness which has been observed during prolonged space missions. Three major areas were investigated: (1) the interaction of visual and vestibular cues in conflict in the human, (2) the plasticity of the vestibulo-ocular reflex in monkeys, and (3) end organ function in the ray with particular emphasis on the effect of ionic concentration

The effect of visual detail on cybersickness:predicting symptom severity using spatial velocity

Abstract. In this work, we examine the effect of visual realism on the severity of cybersickness symptoms experienced by users of virtual environments. We also seek to validate a metric called spatial velocity as a predictor of cybersickness. The proposed metric combines the visual complexity of a virtual scene with the amount of movement within the scene. To achieve this, we prepared two virtual scenes depicting the same environment with a variable level of detail. We recruited volunteers who were exposed to both scenes in two separate sessions. We obtained the sickness ratings after both sessions and saved the data required for spatial velocity calculations. After comparing the sickness ratings between the two scenes, we found no evidence of the visual realism playing any significant role in the generation of cybersickness symptoms. The spatial velocity also proved inadequate in characterizing the difference in visual complexity and correlated poorly with all the observed sickness scores.Visuaalisen yksityiskohtaisuuden vaikutus VR-pahoinvointiin : oireiden vakavuuden ennustaminen käyttäen SV-metriikkaa. Tiivistelmä. Tässä työssä tutkimme sitä, millainen vaikutus virtuaalisten ympäristöjen graafisella yksityiskohtaisuudella on VR-pahoinvointiin. Pyrimme myös validoimaan "spatial velocity" -nimisen mittasuureen kyvyn ennustaa VR-pahoinvoinnin oireiden vakavuutta. Kyseisen mittasuureen etuna on, että se yhdistää visuaalisen kompleksisuuden ja ympäristössä koetun liikkeen yhdeksi suureeksi. Tutkimusta varten valmistimme kaksi virtuaaliympäristöä, joissa mallinnettiin Oulun yliopiston kampusaluetta. Toinen ympäristö pyrki mahdollisimman realistiseen esitystapaan, kun taas toisessa yksityiskohtien määrä minimoitiin. Koetta varten värväsimme 18 vapaaehtoista. Vapaaehtoiset altistettiin kummallekin ympäristölle kahdessa noin kymmenen minuutin mittaisessa kokeessa. Vapaaehtoisten kokeman VR-pahoinvoinnin vakavuutta arvioitiin kunkin kokeen jälkeen täytetyillä kyselylomakkeilla. Kokeiden aikana tallensimme myös SV laskentaan tarvittavat tiedot. Verrattuamme koeolosuhteiden tuloksia, emme löytäneet todisteita siitä, että ympäristön graafisten yksityiskohtien määrällä olisi merkittävää vaikutusta koettuun pahoinvointiin. Käytetty SV metriikka ei myöskään kyennyt erottelemaan ympäristöjä oletetulla tavalla, eivätkä lasketut arvot korreloineet merkittävästi minkään mitatun pahoinvointisuureen kanssa

Visually Induced Motion Sickness Estimation and Prediction in Virtual Reality using Frequency Components Analysis of Postural Sway Signal

The paper proposes a method for estimating and predicting visually induced motion sickness (VIMS) occurring in a navigation task in a 3D immersive virtual environment, by extracting features from the body postural sway signals in both the time and frequency domains. Past research showed that the change in the body postural sway may be an element for characterizing VIMS. Therefore, we conducted experiments in a 3D virtual environment where the task was simply a translational movement with different navigation speeds. By measuring the evolution of the body's center of gravity (COG), the analysis of the sway signals in the time domain showed a dilation of the COG's area, as well as a change in the shape of the area. Frequency Components Analysis (FCA) of the sway signal gave an efficient feature to estimate and predict the level of VIMS. The results provide promising insight to better monitor sickness in a virtual reality application.FUI Callist

Visually Guided Control of Movement

The papers given at an intensive, three-week workshop on visually guided control of movement are presented. The participants were researchers from academia, industry, and government, with backgrounds in visual perception, control theory, and rotorcraft operations. The papers included invited lectures and preliminary reports of research initiated during the workshop. Three major topics are addressed: extraction of environmental structure from motion; perception and control of self motion; and spatial orientation. Each topic is considered from both theoretical and applied perspectives. Implications for control and display are suggested

Brainstem processing of vestibular sensory exafference: implications for motion sickness etiology

Penultimate version of manuscript accepted 4/20/14, and after minor edits, published online May 18, 2014 at Springer Online First as DOI 10.1007/s00221-014-3973-2The origin of the internal “sensory conflict” stimulus causing motion sickness has been debated for more than four decades. Recent studies show a subclass of neurons in the vestibular nuclei and deep cerebellar nuclei that respond preferentially to passive head movements. During active movement, the semicircular canal and otolith input (“reafference”) to these neurons is cancelled by a mechanism comparing the expected consequences of self-generated movement (estimated with an internal model- presumably located in the cerebellum) with the actual sensory feedback. The un-cancelled component (“exafference”) resulting from passive movement normally helps compensate for unexpected postural disturbances. Notably, the existence of such vestibular “sensory conflict” neurons had been postulated as early as 1982, but their existence and putative role in posture control, motion sickness has been long debated. Here we review the development of “sensory conflict” theories in relation to recent evidence for brainstem and cerebellar reafference cancellation, and identify some open research questions. We propose that conditions producing persistent activity of these neurons, or their targets, stimulates nearby brainstem emetic centers – via an as yet unidentified mechanism. We discuss how such a mechanism is consistent with the notable difference in motion sickness susceptibility of drivers as opposed to passengers, human immunity to normal self-generated movement, and why head restraint or lying horizontal confers relative immunity. Finally, we propose that fuller characterization of these mechanisms, and their potential role in motion sickness could lead to more effective, scientifically based prevention and treatment for motion sickness.Dr. Oman was supported in part by the National Space Biomedical Research Institute through NASA NCC 9-58. Dr. Cullen’s research was supported by the Canadian Institutes of Health Research (CIHR), the National Institutes of Health (DC002390), and the Fonds Que´be´cois de la Recherche sur la Nature et les Technologies (FQNRT), and US National Institute of Health Grant R01 DC239

Aerospace medicine and biology. A continuing bibliography (supplement 231)

This bibliography lists 284 reports, articles, and other documents introduced into the NASA scientific and technical information system in March 1982

Psychological and psychophysical aspects of spatial orientation.

These studies were undertaken to investigate the psychological and psychophysical factors that mediate spatial orientation/disorientation in both healthy and patient populations. PERCEPTION OF ANGULAR VELOCITY: Using a new method of examining perception of rotation this study found a similarity between the sensation and ocular responses following velocity step stimuli. Both decayed exponentially with a time constant of circa 15 seconds following rotation in yaw; circa 7 seconds following rotation in roll. Both the ocular and sensation responses were significantly reduced following repeated vestibular and optokinetic stimulation. The test was conducted with patients suffering from congenital nystagmus, ophthalmoplegia or cerebellar lesions, all of whom had markedly reduced post-rotational sensation responses of approximately 7 to 9 seconds. ADAPTATION TO OSCILLOPSIA: Labyrinthine defective subjects were found to prefer less self- motion when viewing a moving video-image than either ophthalmoplegia subjects or normal controls. The results suggest that adaptation to oscillopsia may be related to an active approach to recovery (i.e. high external locus of control) and also to increased tolerance to retinal slip. This serves to illustrate the coactive role of psychological and psychophysical mechanisms in adaptation to vestibular disorders. INVESTIGATION OF PSYCHOLOGICAL AND PSYCHOSOCIAL FACTORS: This questionnaire- based study aimed to examine adjustment to illness in patients with balance disorders and with congenital nystagmus. The study identified a greater use of emotion-focused coping strategies than problem-focused strategies. It highlighted the prevaience of anxiety and depression among these patients and pointed towards several psychosocial variables (locus of control, self-esteem and social support) that play a significant role in the coping behaviour of these patients. MENSTRUATION, MIGRAINE AND MOTION SICKNESS: The relationship between hormonal cycles and migraine and motion sickness is poorly understood. The study demonstrated that motion sickness and headache occurred independently although exposure to rough seas could be a specific migraine trigger in certain individuals who did not otherwise suffer attacks. Female subjects were more prone to motion sickness around the period of menstruation and less so around ovulation