Perceived body position and the visual horizontal

Mast, Fred W.; Jarchow, Thomas

doi:10.1016/0361-9230(96)00132-3

Cited by 60 publications

(55 citation statements)

References 9 publications

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“…For an ideal observer, all psychometric functions would resemble a step centered at zero. Across the five reference orientations (0°, Ϯ45°, or Ϯ90°), the psychometric data indicate underestimations and overestimations of perceived body angle, but no consistent bias, which resembles previous reports (Mittelstaedt, 1983;Mast and Jarchow, 1996;Jarchow and Mast, 1999;Van Beuzekom et al, 2001) that body-tilt perception is accurate on average. We fitted psychometric curves through these data (see Materials and Methods, Eq.…”

Section: Psychometric Resultssupporting

confidence: 84%

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Multisensory Processing in Spatial Orientation: An Inverse Probabilistic Approach

Clemens

Vrijer²,

Selen³

et al. 2011

J. Neurosci.

134

298

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Most evidence that the brain uses Bayesian inference to integrate noisy sensory signals optimally has been obtained by showing that the noise levels in each modality separately can predict performance in combined conditions. Such a forward approach is difficult to implement when the various signals cannot be measured in isolation, as in spatial orientation, which involves the processing of visual, somatosensory, and vestibular cues. Instead, we applied an inverse probabilistic approach, based on optimal observer theory. Our goal was to investigate whether the perceptual differences found when probing two different states-body-in-space and head-in-space orientation-can be reconciled by a shared scheme using all available sensory signals. Using a psychometric approach, seven human subjects were tested on two orientation estimates at tilts Ͻ120°: perception of body tilt [subjective body tilt (SBT)] and perception of visual vertical [subjective visual vertical (SVV)]. In all subjects, the SBT was more accurate than the SVV, which showed substantial systematic errors for tilt angles beyond 60°. Variability increased with tilt angle in both tasks, but was consistently lower in the SVV. The sensory integration model fitted both datasets very nicely. A further experiment, in which supine subjects judged their head orientation relative to the body, independently confirmed the predicted head-on-body noise by the model. Model predictions based on the derived noise properties from the various modalities were also consistent with previously published deficits in vestibular and somatosensory patients. We conclude that Bayesian computations can account for the typical differences in spatial orientation judgments associated with different task requirements.

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Section: Psychometric Resultssupporting

confidence: 84%

“…ever, neither previous findings (Mittelstaedt, 1983;Mast and Jarchow, 1996;Jarchow and Mast, 1999;Van Beuzekom et al, 2001) nor the present results (Figs. 3,4), showed such systematic errors across subjects.…”

Section: Sensory Integration Modelcontrasting

confidence: 53%

Multisensory Processing in Spatial Orientation: An Inverse Probabilistic Approach

Clemens

Vrijer²,

Selen³

et al. 2011

J. Neurosci.

134

298

View full text Add to dashboard Cite

show abstract

“…For tilt angles exceeding 60º, they also observed a correlation between errors made in body tilt estimates and errors produced in the subjective vertical task. Conversely, Mast and Jarchow (1996) recorded the subjective visual horizontal when subjects had the feeling that they were lying horizontally on the side. They found a paradoxical phenomenon.…”

mentioning

confidence: 99%

Contribution of somesthetic cues to the perception of body orientation and subjective visual vertical

Trousselard

Cian

Nougier

et al. 2003

Perception & Psychophysics

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Without relevant visual cues, the subjective visual vertical (SVV) is biased in roll-tilted subjects toward the body axis (Aubert or A-effect). This study focused on the role of the somatosensory system with respect to the SVV and on whether somesthetic cues act through the estimated body tilt. The body cast technology was used to obtain a diffuse tactile stimulation. An increased A-effect was expected because of a greater underestimation of the body position in the body cast. Sixteen subjects placed in a tilt chair were rolled sideways from 0º to 105º. They were asked to verbally indicate their subjective body position and then to adjust a luminous line to the vertical under strapped and body cast conditions. Results showed a greater A-effect ( p < .001) but an overestimation of the body orientation ( p < .01) in the body cast condition for the higher tilt values (beyond 60º). Since the otolith organs produced the same gravity response in both conditions, errors were due to a change in somesthetic cues. Visual and postural errors were not directly related (no correlation). However, the angular distance between the apparent body position and the SVV remained stable, suggesting that the change in somatosensory pattern inputs has a similar impact on the cognitive processes involved in assessing the perception of external space and the sense of self-position.

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“…Whereas for perceived horizontal self-adjustments in complete darkness also suggest high accuracy (Mittelstaedt 1983;Mast and Jarchow 1996), our subjects moved the chair to larger roll angles than actually required whenever the desired chair roll angle was 75° RED. These deviations may originate from the same, likely visiondependent, mechanism that causes the A-effect in the SVV (Aubert 1861;Howard 1982).…”

Section: Visually-guided Self-adjustments In the Roll Plane Show An Amentioning

confidence: 67%

Visually guided adjustments of body posture in the roll plane

2013

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Body position relative to gravity is continuously updated to prevent falls. Therefore, the brain integrates input from the otoliths, truncal graviceptors, proprioception and vision. Without visual cues estimated direction of gravity mainly depends on otolith input and becomes more variable with increasing roll-tilt. Contrary, the discrimination threshold for object orientation shows little modulation with varying roll orientation of the visual stimulus. Providing earth-stationary visual cues, this retinal input may be sufficient to perform self-adjustment tasks successfully, with resulting variability being independent of whole-body roll orientation. We compared conditions with informative (earth-fixed) and non-informative (body-fixed) visual cues. If the brain uses exclusively retinal input (if earth-stationary) to solve the task, trial-to-trial variability will be independent from the subject's roll orientation. Alternatively, central integration of both retinal (earth-fixed) and extra-retinal inputs will lead to increasing variability when roll-tilted. Subjects, seated on a motorized chair, were instructed to (1) align themselves parallel to an earth-fixed line oriented earth-vertical or roll-tilted 75°clockwise; (2) move a body-fixed line (aligned with the body-longitudinal axis or roll-tilted 75°counter-clockwise to it) by adjusting their body position until the line was perceived earth-vertical. At 75°right-ear-down position, variability increased significantly (p < 0.05) compared to upright in both paradigms, suggesting that, despite the earth-stationary retinal cues, extra-retinal input is integrated. Self-adjustments in the roll-tilted position were significantly (p < 0.01) more precise for earth-fixed cues than for body-fixed cues, underlining the importance of earth-stable visual cues when estimates of gravity become more variable with increasing whole-body roll. ABSTRACTBody position relative to gravity is continuously updated to prevent falls. Therefore the brain integrates input from the otoliths, truncal graviceptors, proprioception and vision.Without visual cues estimated direction of gravity mainly depends on otolith input and becomes more variable with increasing roll-tilt. Contrary, the discrimination threshold for object orientation shows little modulation with varying roll orientation of the visual stimulus.Providing earth-stationary visual cues, this retinal input may be sufficient to perform selfadjustment tasks successfully, with resulting variability being independent of whole-body roll orientation. We compared conditions with informative (earth-fixed) and non-informative (body-fixed) visual cues. If the brain uses exclusively retinal input (if earth-stationary) to solve the task, trial-to-trial variability will be independent from the subject's roll orientation.Alternatively, central integration of both retinal (earth-fixed) and extra-retinal inputs will lead to increasing variability when roll-tilted. Subjects, seated on a motorized chair, were instructed to 1) align themse...

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Perceived body position and the visual horizontal

Cited by 60 publications

References 9 publications

Multisensory Processing in Spatial Orientation: An Inverse Probabilistic Approach

Multisensory Processing in Spatial Orientation: An Inverse Probabilistic Approach

Contribution of somesthetic cues to the perception of body orientation and subjective visual vertical

Visually guided adjustments of body posture in the roll plane

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