Citation

Kuno S, Kawakita T, Kawakami O, Miyake Y, Watanabe S. Jpn. J. Physiol. 1999; 49(5): 417-424.

Affiliation

Department of ophthalmology, Nagoya University School of Medicine, Showa-ku, Nagoya, 466-0065, Japan.

Copyright

(Copyright © 1999, Physiological Society of Japan)

DOI

unavailable

PMID

10603425

Abstract

PURPOSE: Human posture is controlled by a combination of vestibular, somatosensory and visual information. This paper is concerned with postural readjustment responses induced by vection. In the visual control of posture, visually-induced perception of self-motion plays an important role and is called vection. Vection is difficult to measure quantitatively because it is a highly subjective phenomenon. HYPOTHESIS: An optokinetic stimulus that moves in depth induces vection. We hypothesize that the magnitude of the visually-induced body sway is correlated with the degree of vection. METHODS: A depth optokinetic stimulus (DOKS) was projected onto a head-mounted display (HMD) worn by standing subjects. The DOKS consisted of a random dot pattern that was perceived three-dimensionally and moved in depth sinusoidally. Vection was estimated in two ways, a verbal assessment and a joystick maneuver. In addition, visually-induced body sway was measured by monitoring five reference points on the body by two video-motion analyzers. RESULTS: The magnitude of the subjective vection was highly correlated with visually-induced body sway and was strongly dependent on the velocity of the visual stimulus. The ankle joint was pivoted during visually-induced body sway and acted as a motion initiator. When the magnitude of body sway was large, the body movement was adjusted at the hip and head-neck joints. CONCLUSIONS: The high correlation between vection and body sway suggests that vection can be estimated quantitatively by measuring visually-induced body sway.

Language: en