Framing visual roll-motion affects postural sway and the subjective visual vertical

Abstract

Effects of visual roll-motion on postural sway and the subjective visual vertical (SVV) often is studied using mechanical devices, whereas electronic displays offer cheaper and more flexible alternatives. These devices typically emit and reflect light scattered by the edges of the screen, providing Earth-fixed cues of verticality. These cues may decrease the effects of rotating stimuli, a possibility that has not been studied explicitly before in one experimental design. We exposed 16 participants to a visual dot pattern, either stationary, or rotating in roll, that was or was not surrounded by a visible Earth-fixed reference frame. To eliminate unintended visual cues, the experiment was performed in complete darkness and participants wore neutral density goggles passing only 1% of light. Postural sway was measured using a force platform. SVV measurements were obtained from a visible rod. To monitor the participants, motion sickness severity was obtained with an 11-point rating scale. Results showed that the presence of an Earth-fixed frame significantly decreased the effect of the rotating pattern on postural sway and SVV deviations. Therefore, when studying subjective verticality related effects of visual stimuli, it is imperative that all visual Earth-fixed cues are not just minimized but completely eliminated. The observation that an Earth-fixed frame significantly decreased the effect of the rotating pattern on both postural sway and the SVV points towards a common neural origin, possibly involving a neural representation of verticality. Finally, we showed that an electronic screen can yield similar effect sizes as those taken from the literature using mechanical devices.Electronic supplementary materialThe online version of this article (doi:10.3758/s13414-016-1150-3) contains supplementary material, which is available to authorized users.

Perception of Upright: Multisensory Convergence and the Role of Temporo-Parietal Cortex

“…In the case of a square frame, the visual vertical estimate is biased by the frame orientation, which is known as the rod-and-frame effect. The frame effect can be robust and, for example, significantly decrease SVV errors induced by rotating backgrounds ( 122 , 123 ). This visual effect for the most part depends on the viewing distance and the head tilt position.…”

Perception de la verticale en présence d’indices d’orientation visuels ou sonores : vers une dépendance allocentrée ?

“…Cette étude pilote précède la tenue d'une expérimentation plus large avec des effectifs plus importants intégrant des individus situés aux extrêmes du continuum (i.e., fortement DC ou IC). Nous espérons dès lors pouvoir observer des effets plus marqués de l'inclinaison d'une scène allocentrée sur la VS. En outre, nos scènes allocentrées ayant la particularité d'être dynamiques, il serait intéressant d'enrichir nos données de dépendance à l'égard du champ issues du RFT par un test de type « visual roll-motion » (Lubeck, Bos, & Stins, 2016). Les effets de la mise en rotation d'un nuage de points sur la VS pourraient être croisés avec les données issues du RFT et nous donner une information plus précise sur la sensibilité individuelle de nos participants aux perturbations issues de l'environnement visuel proche.…”

Postural sway in the moving room scenario: New evidence for functional dissociation between self-motion perception and postural control

“…Duration is the total time the button is pressed during each trial. Vection is by nature a subjective sensation, and the approach of button pressing during the trial and magnitude estimation methods after each session allows us to quantify it using well-established methods [20][21][22][23][24]38].…”

“…Investigating the potential role of consciousness in quiet standing requires a setup with low-amplitude, low-frequency conditions. Previous studies have shown that vection can impact postural response [20][21][22][23][24]; however, the adopted visual-stimulus speed was high in order to create conditions where vection would be evoked and constant speed or direction (contraction, expansion, rotation) were used to maintain a continuous feeling of vection. Such rapid visual stimuli lie far outside the range of natural human motion, and therefore evoke an acute, high-alert body reaction.…”