Optokinetic after-nystagmus under prolonged alteration in the direction of gravity.
Optokinetic nystagmus (OKN) and after-nystagmus (OKAN) show different responses depending on the direction of gravity with respect to the head and body. In 13 normal healthy persons (10 experimental and 3 control subjects), we studied the OKAN evoked by horizontal and vertical stimuli, in upright, side-lateral, and repeated upright positions along a time course of more than 6 h. The results showed continuous modifications of OKAN, the degree increasing with time. Lateral tilt produced different effects on the intrinsic vertical and horizontal optokinetic oculomotor systems.
Igarashi
M
M
University Research Center, Nihon University, Tokyo, Japan.
Watanabe
Y
Y
Ikeda
M
M
Tomita
H
H
Kotanagi
Y
Y
D000293:Adolescent; D000328:Adult; D006112:Gravitation; D006801:Humans; D008297:Male; D017120:Nystagmus, Optokinetic; D011187:Posture; D013997:Time Factors