Ocular accommodation neurons in brain stem of the alert cat

Ten "ocular accommodation" units in the brain stem reticular formation of alert, unanesthetized cats were studied. While the cat's head was immobilized with a skull mount, ocular accommodation was induced by stimuli presented to the right eye. The consensual accommodation response was measured in the left eye with an infrared optometer. There was a close association between the accommodative demand of the visual stimulus, the discharge frequency of brain stem accommodation neurons, and consequent ocular accommodation. Controls for eye movements, pupil size, et., were applied. The accommodation neurons described were found in brain stem areas not traditionally associated with the accommodative mechanism.