Perceived Horizontal Body Position in Healthy and Paraplegic Subjects: Effect of Centrifugation

Jarchow, Thomas; Wirz, Markus; Haslwanter, Thomas; Dietz, Volker; Straumann, Dominik

doi:10.1152/jn.01129.2002

Cited by 13 publications

(7 citation statements)

References 12 publications

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“…They concluded that somatic graviceptors exist in the human trunk for the perception of own body orientation, in addition to the well-known visualvestibular system for the perception of both the orientation of the visual world and the head in space [9]. Similar conclusions were drawn by Jarchow et al [10]. Further evidence was reported by Kaptein and van Gisbergen [11], who observed a sudden discontinuity in normal subjects' perception of the SVV for body tilts larger than 135°.…”

Section: Introductionsupporting

confidence: 56%

"Pusher syndrome" following cortical lesions that spare the thalamus

et al. 2006

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Stroke patients with "pusher syndrome" show severe misperception of their own upright body orientation although visual-vestibular processing is almost intact. This dissociation argues for a second graviceptive system in humans for the perception of body orientation. Recent studies revealed that the posterior thalamus is an important part of this system. The present investigation aimed to study the cortical representation of this system beyond the thalamus. We evaluated 45 acute patients with and without contraversive pushing following left-or right-sided cortical lesions sparing the thalamus. In both hemispheres, the simple lesion overlap associated with contraversive pushing typically centered on the insular cortex and parts of the postcentral gyrus. The comparison between pusher patients and controls who were matched with respect to age, lesion size, and the frequency of spatial neglect, aphasia and visual field defects revealed only very small regions that were specific for the pusher patients with cortical damage sparing the thalamus. Obviously, the cortical structures representing our control of upright body orientation are in close anatomical proximity to those areas that induce aphasia in the left hemisphere and spatial neglect in the right hemisphere when lesioned. We conclude that in addition to the subcortical area previously identified in the posterior thalamus, parts of the insula and postcentral gyrus appear to contribute at cortical level to the processing of the afferent signals mediating the graviceptive information about upright body orientation.

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Section: Introductionsupporting

confidence: 56%

"Pusher syndrome" following cortical lesions that spare the thalamus

et al. 2006

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“…Correct depth perception relies on an accurate knowledge of the three dimensional orientation of the head and eyes (Blohm et al, 2008) in order to correctly interpret disparities over the whole visual field. Eye position does not seem to be affected by adopting a supine posture (Bockisch & Haslwanter, 2001) but knowledge of body orientation when lying supine is poor with large systematic errors and poor reliability (Jarchow, Wirz, Haslwanter, Dietz, & Straumann, 2003;Mast & Jarchow, 1996). Thus, a supine posture may not be so accurately calibrated against experience of depth.…”

Section: Discussionmentioning

confidence: 99%

Perceived distance depends on the orientation of both the body and the visual environment

Harris

Mander

2014

Journal of Vision

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Models of depth perception typically omit the orientation and height of the observer despite the potential usefulness of the height above the ground plane and the need to know about head position to interpret retinal disparity information. To assess the contribution of orientation to perceived distance, we used the York University Tumbled and Tumbling Room facilities to modulate both perceived and actual body orientation. These facilities are realistically decorated rooms that can be systematically arranged to vary the relative orientation of visual, gravity, and body cues to upright. To assess perceived depth we exploited size/distance constancy. Observers judged the perceived length of a visual line (controlled by a QUEST adaptive procedure) projected on to the wall of the facilities, relative to the length of an unseen iron rod held in their hands. In the Tumbled Room (viewing distance 337 cm) the line was set about 10% longer when participants were supine compared to when they were upright. In the Tumbling Room (viewing distance 114 cm), the line was set about 11% longer when participants were either supine or made to feel that they were supine by the orientation of the room. Matching a longer visual line to the reference rod is compatible with the opposite wall being perceived as closer. The effect was modulated by whether viewing was monocular or binocular at a viewing distance of 114 cm but not at 337 cm suggesting that reliable binocular cues can override the effect.

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“…For conditions in which the subject was horizontal with head at the axis of the centrifuge, research on perception was used to inform the choice of radius considered for centripetal acceleration detection. It is well known that a horizontal subject rotating on a centrifuge does not detect linear acceleration simply at the head [15, 22–26, 30]. Instead, for a subject with legs extended, the “center” of centripetal acceleration detection has been found to be caudal to the vestibular system, anywhere from 30 cm [24] to 59 cm [26] depending on the method of measurement.…”

Section: Methodsmentioning

confidence: 99%

Asymmetries and three-dimensional features of vestibular cross-coupled stimuli illuminated through modeling

Holly

Masood

Bhandari

2016

VES

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Head movements during sustained rotation can cause angular cross-coupling which leads to tumbling illusions. Even though angular vectors predict equal magnitude illusions for head movements in opposite directions, the magnitudes of the illusions are often surprisingly asymmetric, such as during leftward versus rightward yaw while horizontal in a centrifuge. This paper presents a comprehensive investigation of the angular-linear stimulus combinations from eight different published papers in which asymmetries were found. Interactions between all angular and linear vectors, including gravity, are taken into account to model the three-dimensional consequences of the stimuli. Three main results followed. First, for every pair of head yaw movements, an asymmetry was found in the stimulus itself when considered in a fully three-dimensional manner, and the direction of the asymmetry matched the subjectively reported magnitude asymmetry. Second, for pitch and roll head movements for which motion sickness was measured, the stimulus was found symmetric in every case except one, and motion sickness generally aligned with other factors such as the existence of a head rest. Third, three-dimensional modeling predicted subjective inconsistency in the direction of perceived rotation when linear and angular components were oppositely-directed, and predicted surplus illusory rotation in the direction of head movement.

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Perceived Horizontal Body Position in Healthy and Paraplegic Subjects: Effect of Centrifugation

Cited by 13 publications

References 12 publications

"Pusher syndrome" following cortical lesions that spare the thalamus

"Pusher syndrome" following cortical lesions that spare the thalamus

Perceived distance depends on the orientation of both the body and the visual environment

Asymmetries and three-dimensional features of vestibular cross-coupled stimuli illuminated through modeling

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