[Experimental study on the eye movements induced by the electrical stimulation of the cerebellar nucleus in the...

The purpose of this study is to investigate the induced eye movements by the cerebellar nuclei stimulation in the rabbits. Forty-five pigmented rabbits were used in this experiments. The cerebellar nuclei, especially medial nucleus, were stimulated electrically and the induced eye movements were observed. The results were as follows. 1. The horizontal nystagmus was produced by the electrical stimulation of the medial, anterior interposed, or posterior interposed nuclei. 2. The horizontal nystagmus towards the ipsilateral to the stimulated side was observed when the caudal portion of the medial nucleus was stimulated. On the other hand, the horizontal nystagmus towards the contralateral to the stimulated side was observed when the rostral portion of the medial nucleus was stimulated. 3. The latency of the field potential in the vestibular nucleus by stimulating the medial cerebellar nucleus, and that in the reverse situation, were 0.7 to 1.1 msec. 4. After the destruction of the lateral vestibular nucleus, no nystagmus was elicited by the stimulation of the medial cerebellar nucleus. From these results, it can be concluded that there is the monosynaptic connection between the medial cerebellar nucleus and the lateral vestibular nucleus. This indicates that the stimulation of the medial cerebellar nucleus produces the excitation of the vestibular nucleus via the cerebello-vestibular fibers and produces the nystagmus in the pigmented rabbits.