[Eye movements in animals with extirpated cerebrocortical oculomotor centers]

An investigation of dogs with removed temporal and sincipito-occipital cortical centres of the eye movements demonstrated that a number of properties of the vestibular nystagmus evoked by the rotation of the animal remain the same as they had been in this very same animal prior to the operation. These centres do not control the nature of the nystagmic movement that consists of a slow and a fast components, the combined movements of the right and left eyes, the direction of the nystagmus, the range and the nature marking the distribution of the maximal movement and of the most frequent movements during the action of the stimulus and the symmetry of the labyrinthine function. At the same time, the dissociation of the cortical centres of the eye movements brings on shortening of the vestibular post-rotational nystagmus, activation of the mechanism that monitors the rhythmic tonic deflections of the eyes, this causing diminution in the number of nystagmic eye movements and disruption in the rhythm of their movement. It also activates arbitrary movements of the eyes that occasionally turn into a spontaneous nystagmus. The abundance of arbitrary eye movements following vestibular stimulation is of frequent occurrence in children, victims of cerebral paralysis of childhood combined wit- depressed cortical function.