RÔLE OF VESTIBULAR NUCLEI IN THE CORTICAL INNERVATION OF THE EYE MUSCLES

Abstract

It is almost generally agreed that the posterior longitudinal fasciculus carries not only labyrinthine but also voluntary impulses to the muscles of the eye (Spitzer,¹ Muskens² and Spiegel and Tokay³), but it is still uncertain how the cortical impulses enter this bundle. Marburg,⁴ for instance, conjectured that these impulses, after having traveled within the internal capsule and in the peduncle and crossed in the midbrain or the cranial part of the pons, enter directly into this bundle; in such a case, one would expect to find degeneration in the fasciculus longitudinalis posterior after injuries of the cortical centers or of the internal capsule, but this has never been observed. Hence, subcortical gaze centers have been conjectured in many places: in the thalamus (Spitzer¹), in the corpora quadrigemina (Adamük⁵), in the sixth nucleus (Wernicke⁶) and in the formatio reticularis (Monakow and Bárány⁷). But,