Studies on the Interrelationship between the Vestibular Semicircular Canals and the Extraocular Muscles in Rabbits and Cats

가토(家兎) 및 가묘(家猫)에 있어서 전정반규관(前庭半規管)과 외안근(外眼筋)의 상관성(相關性)에 관(關)한 연구(硏究)

The present experiment was carried out, in the rabbit and cat, in order to explore functional interrelationship between the vestibular semicircular canals and extraocular muscles, which are involved in the vestibulooculomotor reflex as the receptor and effector organ respectively. Semicircular canals were subjected to electrical stimulation, lymphatic fluid flow or acute freezing, and responses of the extraocular muscles were recorded in terms of changes in electromyographic activity and isometric tension. Electrical stimulation of a unilateral canal elicited contraction of the superio-medial muscle group (superior oblique, superior rectus and medial rectus muscles) in the ipsilateral eye and the inferio-lateral muscle group (inferior oblique, inferior rectus and lateral rectus muscles) in the contralateral eye. Thus a simple and distinct axiom was found in the pattern of the reflex-response of the extraocular muscles. Inhibition of the unilateral canals elicited the extraocular muscle responses contrary to those observed by excitation of the canal. Based on the present experimental results, it was demonstrated that the functional interrelations between the semicircular canals and extraocular muscles are rather equivalent in the frontal eyed cats (with binocular vision) and lateral eyed rabbits (with monocular vision). Therefore the previous thesis that the vestibuloocular relations vary from species to species awaits experimental reevaluation.