The effect of gravity on galvanic nystagmus in rabbits.

The effect of gravity on a galvanic nystagmus provoked in rabbits was investigated. Weightlessness increased the amplitude but decreased the frequency as well as the speed of the nystagmus. During continuous galvanic stimulation the provoked nystagmus disappeared spontaneously after a period of 60-120 seconds. Weightlessness was able to arouse this nystagmus again. An explanation of this phenomenon might be that galvanic nystagmus undergoes a modifying effect from the vestibular maculae and their state of stimulation.