[Comparative neurobiology of the organization of gaze-stabilizing reflex systems in vertebrates]

During locomotion gaze is stabilized against passive head movements by compensatory eye movements. The efficacy and the neuronal organization of optokinetic and vestibular reflexes of different vertebrate species is compared. Besides many similarities between species a number of differences can be found as well. Increase in the efficacy of compensatory reflexes is not correlated with an increase in the efficacy of basic neuronal circuits but with the appearance of functionally new connections and of new network properties. This increasingly higher complexity allows to maintain gaze stability at increasingly higher speeds of locomotion or to suppress these reflexes during visual pursuit of a moving object.