Modification of Vestibular Responses as a Function of Rate of Rotation About an Earth-Horizontal Axis

Perception of the Body in Space: Mechanisms

“…After 15-30 s of constant-angular-velocity rotation, however, the semicircular canal signals have decayed toward zero, except for a small remaining gravity-sensitive modulation. Nevertheless the perception of the actual continuous rotation remains during the stimulation (4,6,35,76). Clearly this is a case where there is a conflict between semicircular canal information, which decays to its rest state and does not indicate any rotation (although strictly speaking it supports any constantvelocity hypothesis) and dynamic otolith information, which is consistent with continuous rotation.…”

Motion Sickness Susceptibility: A Retrospective Comparison of Laboratory Tests.

“…The exact nature 9 f the TART stimulus is still in question; however, "I according to classical vestibulir theory, as off-vertical rotation commences, the semicircular canals and otolith ortians would yield "concordant" signals of rotation. After rotation has been sustained for about 40 seconds, the semicircular canal input would have returned to near baseline level, yet nystagmus is augmented throughout offvertical rotation and persists far beyond its expected decay (6,7). It is possible that tthe augmented response as well as the nauseogenic effects that develop during this prolonged (90 second) rotation is attributable to otolithic modulation of the spontaneous ampullary nerve input (cf.…”

“…Eye movements recorded during this pro-* cedure as a part of the over-all evaluation are not considered in this report. However, it is pertinent to note that mental arithmetic was used to maintain alertness because of its influence on nystagmus recordings (5,14), and that mental arithmetic may reduce the probability of motion sickness in a short exposure (6). Possibly counteracting th= ,.,eliorative effect of mental arithmetic is the fact that each subject was informed that he could stop the test at any time and that he should stop if vomiting was imminent.…”

“…Subjects were typically tested over a 2-day period. In a few cases, scheduling restraints or equipment failure prevented completion of all tests, In the TART the erectly standing subject-was securely fastened in a litter device capable of rotation about an axis that could be varied in orientation relative to gravity (6,7). The subject was blindfolded and tested in a darkened room.…”

Nystagmus Responses during Rotation about a Tilted Axis,

“…The time constant of nystagmus decay, measured from the onset of constant velocity rotation, was 77 seconds when W = 66 deg/sec, but was only 45 seconds when W = 102 deg/sec and 37 seconds when W = 138 deg/sec. In a previous study (7) where wj = 180 deg/sec, the time constant of nystagmus decay was 18 seconds.…”