Effects of a visual frame and of low radial accelerations on the visually perceived eye level

Raphel, Christian; Barraud, Pierre‐Alain; Koessler, Claude; Cian, Corinne

doi:10.3758/bf03205492

Cited by 9 publications

(19 citation statements)

References 23 publications

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“…Although the subjective visual horizon was not recorded in the present experiment, the occurrence of such a phenomenon is clearly assumed in this study. Other previous works also reported that the subjective visual horizon is lower in darkness (Bringoux et al 2004(Bringoux et al , 2008MacDougall 1903;Raphel and Barraud 1994;Sharp 1934;Stoper and Cohen 1986). This phenomenon may be related to the 30°backward orientation of the saccular and utricular maculae relative to the head (Rosenhal 1972;Bortolami et al 2006).…”

Section: Discussionmentioning

confidence: 84%

Influence of gaze elevation on estimating the possibility of passing under high obstacles during body tilt

2008

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We investigated the influence of gaze elevation on judging the possibility of passing under high obstacles during pitch body tilts, while stationary, in absence of allocentric cues. Specifically, we aimed at studying the influence of egocentric references upon geocentric judgements. Seated subjects, orientated at various body orientations, were asked to perceptually estimate the possibility of passing under a projected horizontal line while keeping their gaze on a fixation target and imagining a horizontal body displacement. The results showed a global overestimation of the possibility of passing under the line, and confirmed the influence of body orientation reported by Bringoux et al. (Exp Brain Res 185(4):673-680, 2008). More strikingly, a linear influence of gaze elevation was found on perceptual estimates. Precisely, downward eye elevation yielded increased overestimations, and conversely upward gaze elevation yielded decreased overestimations. Furthermore, body and gaze orientation effects were independent and combined additively to yield a global egocentric influence with a weight of 45 and 54%, respectively. Overall, our data suggest that multiple egocentric references can jointly affect the estimated possibility of passing under high obstacles. These results are discussed in terms of ''interpenetrability'' between geocentric and egocentric reference frames and clearly demonstrate that gaze elevation is involved, as body orientation, in geocentric spatial localization.

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Section: Discussionmentioning

confidence: 84%

Influence of gaze elevation on estimating the possibility of passing under high obstacles during body tilt

2008

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“…Their eyesight was normal or corrected to normal, and they were in good healththat is, no vestibular disorders or motion sickness symptoms. Only male subjects were included, for the sake of comparison with the study conducted 3 years ago by Raphel and Barraud (1994), in which only male subjects took part. The experiment was carried out with their signed informed consent in compliance with the Huriet Law (i.e., Helsinki Convention), which governs and regulates human experimentation in France.…”

Section: Methods Subjectsmentioning

confidence: 99%

“…Moreover, there is a logarithmic relationship between very low radial acceleration and lowering of the VPEL, whereas for higher Gi magnitudes and tilts (i.e., Gi 1.25 G [the gravitation force] ), the relationship between radial acceleration and VPEL is linear (Cohen, 1973;Correia et al, 1968). Raphel and Barraud (1994) suggest that the differences between the linear function (higher Gi magnitudes and tilts) and the logarithmic function (lower radial accelerations) may be caused by differences in sense organ stimulation. Indeed, when Gis are strong, the effects of oculogravic illusion are due not only to the influence of the changes in the shearing forces on the utricular and the saccular otolithic membranes, but also to the influence of tactile sensations, kinesthetic sensations, and, sometimes, muscular efforts required to maintain the body in its posture.…”

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confidence: 99%

“…This phenomenon has been explained by an illusory perception of body tilt in pitch and/or by a mechanical action on the otolithic organs (Miller & Graybiel, 1966;Schöne, 1964;Wade & Schöne, 1971). Raphel and Barraud (1994) have shown that lowering of the VPEL is also observed for very low variations of Gis (9.81001 m/sec 2 ) produced by radial acceleration-that is, 0.01 m/sec 2 and above. Moreover, there is a logarithmic relationship between very low radial acceleration and lowering of the VPEL, whereas for higher Gi magnitudes and tilts (i.e., Gi 1.25 G [the gravitation force] ), the relationship between radial acceleration and VPEL is linear (Cohen, 1973;Correia et al, 1968).…”

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confidence: 99%

“…In darkness, the VPEL is more difficult to set and less accurate-lying 3º-6º under the physical eye level-than in an illuminated environment, where the error is less than 3º (Hoppeler, 1913;Matin, 1982Matin, , 1986McDougall, 1903;Nair, 1958;Raphel & Barraud, 1994;Raphel, Barraud, Koessler, & Cian, 1996;Sharp, 1934;Stoper & Cohen, 1986; Figure 1C). For subjects in a supine position, Cohen and Larson (1974) have shown that in darkness, the perceived morphological horizon is "below" Reid's baseline reference value-that is, between 4º and 5º toward the lower part of the body.…”

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confidence: 99%

See 2 more Smart Citations

Effects of supine body position and low radial accelerations on the visually perceived apparent zenith

Raphel

Cian

Barraud

et al. 2001

Perception & Psychophysics

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Difference in the perception of the horizon during true and simulated tilt in the absence of semicircular canal cues

et al. 2006

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Perception of tilt (somatogravic illusion) in response to sustained linear acceleration is generally attributed to the otolithic system which reflects either a translation of the head or a reorientation of the head with respect to gravity (tilt/translation ambiguity). The main aim of this study was to compare the tilt perception during prolonged static tilt and translation between 8 and 20 degrees of tilt relative to the gravitoinertial forces (i.e., G and GIF, respectively) when the semicircular cues were no more available. An indirect measure of tilt perception was estimated by means of a visual and kinesthetic judgment of the gravitational horizon. The main results contrast with the interpretation regarding the tilt/translation ambiguity as the same orientation relative to the shear forces G for the true tilt or GIF in the centrifuge did not induce the same horizon perception. Visual adjustment and arm pointing in the centrifuge were always above the ones observed in a G environment. Part of the lowering of the judgment in the centrifuge may be related to the mechanical effect of GIF on the effectors as shown by the shift of the egocentric coordinates in the direction of GIF. The role of the extravestibular graviceptors in the judgment of the degree of tilt of one's own body relative to G or GIF was discussed.

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Effects of a visual frame and of low radial accelerations on the visually perceived eye level

Cited by 9 publications

References 23 publications

Influence of gaze elevation on estimating the possibility of passing under high obstacles during body tilt

Influence of gaze elevation on estimating the possibility of passing under high obstacles during body tilt

Effects of supine body position and low radial accelerations on the visually perceived apparent zenith

Difference in the perception of the horizon during true and simulated tilt in the absence of semicircular canal cues

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