The Effect of Semicircular Canal Stimulation During Tilting on the Subsequent Perception of the Visual Vertical

Abstract

When a man is accelerated on a centrifuge, the direction of gravitoinertial vertical changes relative to his body. However, a lag occurs in his perception of this change. The hypothesis has been advanced that the perceptual lag in this situation is partly the result of a conflict between signals arising from the semicircular canals and from the otolith organs. To test this hypothesis, subjects were tilted in such a way that they received consistent semicircular canal and otolith signals. This was accomplished simply by tilting them 30 deg from upright in their frontal plane. Immediately after being tilted, these subjects made estimates of the vertical which were approximately accurate, and they continued to make accurate estimates throughout a 140 sec judgment period. The absence of a perceptual lag under these circumstances supports the hypothesis.

Notes

This research was sponsored jointly by the US Army Aeromedical Research Laboratory and the Naval Aerospace Medical Institute, and supported in part by the Office of Advanced Research and Technology, National Aeronautics and Space Administration.

Opinions or conclusions contained in this report are those of the authors. They are not to be construed as necessarily reflecting the view or the endorsement of the Departments of the Army or Navy.