Clement G, Wood SJ, Reschke MF.
Aviat Space Environ Med. 1991 May; 62: 473.
Universities Space Research Institution, Houston, TX.
INTRODUCTION The extent to which slow phase velocity (SPV) of nystagmus elicited by a constant velocity vertical optokinetic stimulation could be modulated with sinusoidal angular head motion in the vertical plane was investigated during the normal gravity conditions and the microgravity phases of parabolic flight. METHODS Six subjects were exposed to 53 deg./sec. optokinetic stimulation in the vertical plane concurrent with pitch sinusoidal oscillations of .25 hz. at 60 deg./sec. peak velocity during the 1-g and 0-g phases of parabolic flight. RESULTS In normal gravity, when the angular head motion and the optokinetic stimulation were in the same direction, the peak SPV was slower than the velocity of the optokinetic display. When the head motion and the optokinetic stimulation were in opposite directions, the peak SPV was equal to the velocity of the optokinetic display. In microgravity, the peak SPV was approximately equal to the velocity of the optokinetic display when head rotation and optokinetic stimulation were in the same direction, and was faster than the velocity of the optokinetic display when head rotation and optokinetic stimulation were in opposite directions. In addition, the interaction of vestibular and optokinetic nystagmus was found to be non-linear in microgravity, especially when the optokinetic stimulation was directed downward. CONCLUSION These results suggest an interaction between the vestibular and optokinetic systems modulated as a function of the gravitational state, and support the observation that visual input is effective in reducing sensory conflict experiences in microgravity.
Publication Types:
Keywords:
- Drug Interactions
- Gravitation
- Head
- Nystagmus, Optokinetic
- Nystagmus, Pathologic
- Photic Stimulation
- Rotation
- Weightlessness
- NASA Center JSC
- NASA Discipline Neuroscience
- NASA Discipline Number 00-00
- NASA Discipline Number 16-10
- NASA Program Flight
- NASA Program Space Physiology and Countermeasures
Other ID:
UI: 102212596
From Meeting Abstracts