Peripheral pathway of proprioceptive fibres from feline extra-ocular muscles. I. A histological study.

The findings of the previous study (1976) involving orbital operations in 12 cats have been confirmed in this study involving intracranial operations in 20 more cats. The perikarya of origin of afferent fibres from feline extra-ocular msucles have been clearly localised to the trigeminal mesencephalic nucleus. The functional subdivision in the nucleus that was noted earlier has been reaffirmed. Thus the caudal or pontine part was the location of cell bodies from the lateral rectus muscle, the intermediate part contained those from the superior oblique, while the other muscles were represented by cell bodies in the rostral part, there being some degree of overlap in the last two zones. In every instance the representation was shown to be bilateral and the total ratio of cellular representation was in the region of 4:1 (ipsilateral-contralateral). The peripheral pathway of the proprioceptive fibres has been shown to be exclusively along the oculomotor, trochlear and abducent nerves which are therefore sensorimotor.