Effect of unilateral section of cervical afferent nerve upon optokinetic response and vestibular nystagmus induced by sinusoidal rotation in guinea pigs

An experiment was carried out in guinea pigs to clarify the effect of unila teral section of cervical afferent nerve (C1-C3) upon optokinetic nystagmus and vestibular nystagmus induced by sinusoidal relation. To produce optoki netic nystagmus and optokinetic after-nystagmus. a random dot pattern was u tilized as visual stimulation at a speed of 30 degrees/s. As for vestibular nystagmus. sinusoidal rotation at a frequency of 0.1 Hz with an amplitude of 120 degrees was used. Results showed that for about a week after the sur gical section of the C1-C3 nerves, directional preponderance of the vestibu lar nystagmus was Found toward the lesion side, whereas no significant chan ge was obtained in optokinetic nystagmus and optokinetic after nystagmus. T his asymmetric change of the vestibular nystagmus was compensated For withi n a week or two. Thus. unilateral section of the cervical afferent nerve pr oduced only a temporary effect on the vestibule-ocular reflex but it had no significant effect oil the optokinetic response.