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Effects of visually simulated roll motion on vection and postural stabilization.

Tanahashi S, Ujike H, Kozawa R, Ukai K - J Neuroeng Rehabil (2007)

Bottom Line: However, self-motion does not need to be consciously perceived to influence postural control.There was no clear habituation for vection and posture, and no effect of stimulus type.Our results suggested that visual stimulus motion itself affects postural control, and supported the idea that the same visual motion signal is used for vection and postural control.

View Article: PubMed Central - HTML - PubMed

Affiliation: School of Science and Engineering, Waseda University, Tokyo, Japan. kg21mj23@toki.waesda.jp

ABSTRACT

Background: Visual motion often provokes vection (the induced perception of self-motion) and postural movement. Postural movement is known to increase during vection, suggesting the same visual motion signal underlies vection and postural control. However, self-motion does not need to be consciously perceived to influence postural control. Therefore, visual motion itself may affect postural control mechanisms. The purpose of the present study was to investigate the effects of visual motion and vection on postural movements during and after exposure to a visual stimulus motion.

Methods: Eighteen observers completed four experimental conditions, the order of which was counterbalanced across observers. Conditions corresponded to the four possible combinations of rotation direction of the visually simulated roll motion stimulus and the two different visual stimulus patterns. The velocity of the roll motion was held constant in all conditions at 60 deg/s. Observers assumed the standard Romberg stance, and postural movements were measured using a force platform and a head position sensor affixed to a helmet they wore. Observers pressed a button when they perceived vection. Postural responses and psychophysical parameters related to vection were analyzed.

Results: During exposure to the moving stimulus, body sway and head position of all observers moved in the same direction as the stimulus. Moreover, they deviated more during vection perception than no-vection-perception, and during no-vection-perception than no-visual-stimulus-motion. The postural movements also fluctuated more during vection-perception than no-vection-perception, and during no-vection-perception than no-visual-stimulus-motion, both in the left/right and anterior/posterior directions. There was no clear habituation for vection and posture, and no effect of stimulus type.

Conclusion: Our results suggested that visual stimulus motion itself affects postural control, and supported the idea that the same visual motion signal is used for vection and postural control. We speculated that the mechanisms underlying the processing of visual motion signals for postural control and vection perception operate using different thresholds, and that a frame of reference for body orientation perception changed along with vection perception induced further increment of postural sway.

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Schematic illustration of the virtual environment. Observers stood at the center of the rectangular space whose wall was textured with one of the two different patterns shown in Figure 2.
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Figure 1: Schematic illustration of the virtual environment. Observers stood at the center of the rectangular space whose wall was textured with one of the two different patterns shown in Figure 2.

Mentions: A moving visual image virtually simulated rotation along the roll axis. As shown in Figure 1, the observer was located at the center of the virtually simulated rectangular space that was 5 × 5 × 3 m (width × depth × height). Two different visual contexts were produced on the inside walls of the rectangular space (Figure 2). One was a random-dot pattern consisting of black dots (2.29 cd/m2) on white walls (43.6 cd/m2), and the other was a pattern that simulated an ordinary room (46.2 cd/m2 for a typical wall). The luminance values indicated were measured for the central 20 deg, and those in the periphery decreased to 31% of the central value due to the characteristics of the back-projection system described below. Despite the luminance difference across the screen, the appearance of images differed very little between the center and the periphery. The diameter of each dot of the random-dot pattern was 4 cm on the wall, and the density of the dot area on the wall was 22%. The pattern simulated an ordinary room including a double door, windows, yellowish-brown wall, linoleum-covered floor, and ceiling with area lighting.


Effects of visually simulated roll motion on vection and postural stabilization.

Tanahashi S, Ujike H, Kozawa R, Ukai K - J Neuroeng Rehabil (2007)

Schematic illustration of the virtual environment. Observers stood at the center of the rectangular space whose wall was textured with one of the two different patterns shown in Figure 2.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2169230&req=5

Figure 1: Schematic illustration of the virtual environment. Observers stood at the center of the rectangular space whose wall was textured with one of the two different patterns shown in Figure 2.
Mentions: A moving visual image virtually simulated rotation along the roll axis. As shown in Figure 1, the observer was located at the center of the virtually simulated rectangular space that was 5 × 5 × 3 m (width × depth × height). Two different visual contexts were produced on the inside walls of the rectangular space (Figure 2). One was a random-dot pattern consisting of black dots (2.29 cd/m2) on white walls (43.6 cd/m2), and the other was a pattern that simulated an ordinary room (46.2 cd/m2 for a typical wall). The luminance values indicated were measured for the central 20 deg, and those in the periphery decreased to 31% of the central value due to the characteristics of the back-projection system described below. Despite the luminance difference across the screen, the appearance of images differed very little between the center and the periphery. The diameter of each dot of the random-dot pattern was 4 cm on the wall, and the density of the dot area on the wall was 22%. The pattern simulated an ordinary room including a double door, windows, yellowish-brown wall, linoleum-covered floor, and ceiling with area lighting.

Bottom Line: However, self-motion does not need to be consciously perceived to influence postural control.There was no clear habituation for vection and posture, and no effect of stimulus type.Our results suggested that visual stimulus motion itself affects postural control, and supported the idea that the same visual motion signal is used for vection and postural control.

View Article: PubMed Central - HTML - PubMed

Affiliation: School of Science and Engineering, Waseda University, Tokyo, Japan. kg21mj23@toki.waesda.jp

ABSTRACT

Background: Visual motion often provokes vection (the induced perception of self-motion) and postural movement. Postural movement is known to increase during vection, suggesting the same visual motion signal underlies vection and postural control. However, self-motion does not need to be consciously perceived to influence postural control. Therefore, visual motion itself may affect postural control mechanisms. The purpose of the present study was to investigate the effects of visual motion and vection on postural movements during and after exposure to a visual stimulus motion.

Methods: Eighteen observers completed four experimental conditions, the order of which was counterbalanced across observers. Conditions corresponded to the four possible combinations of rotation direction of the visually simulated roll motion stimulus and the two different visual stimulus patterns. The velocity of the roll motion was held constant in all conditions at 60 deg/s. Observers assumed the standard Romberg stance, and postural movements were measured using a force platform and a head position sensor affixed to a helmet they wore. Observers pressed a button when they perceived vection. Postural responses and psychophysical parameters related to vection were analyzed.

Results: During exposure to the moving stimulus, body sway and head position of all observers moved in the same direction as the stimulus. Moreover, they deviated more during vection perception than no-vection-perception, and during no-vection-perception than no-visual-stimulus-motion. The postural movements also fluctuated more during vection-perception than no-vection-perception, and during no-vection-perception than no-visual-stimulus-motion, both in the left/right and anterior/posterior directions. There was no clear habituation for vection and posture, and no effect of stimulus type.

Conclusion: Our results suggested that visual stimulus motion itself affects postural control, and supported the idea that the same visual motion signal is used for vection and postural control. We speculated that the mechanisms underlying the processing of visual motion signals for postural control and vection perception operate using different thresholds, and that a frame of reference for body orientation perception changed along with vection perception induced further increment of postural sway.

Show MeSH
Related in: MedlinePlus