[Comparison of the electrophysiologic characteristics of retino-collicular and retino-thalamo-cortical divisions of the visual system of Macaca rhesus monkeys].

In chronic and acute experiments under nembutal anaesthesia, studies have been made on the evoked potentials (EP) elicited by light stimuli in the colliculus superior and in the visual cortex (area 17). It was found that under chronic experiments the EP in the colliculus superior and visual cortex exhibit close (12 +/- 1 and 12 +/- 2 msec. respectively) latent periods; refractory periods determined by paired flashes for both of the parts are equal to 50--70 msec. Critical frequency for EP reproduction of rhythmic flashes in both visual centers is also identical, reaching 20--25/sec. EP with a short latent period equal to that of the EP in the visual cortex were also detected in the frontal and motor cortex, as well as in the hippocamp. The problem of telencephalization of the retinotectal path of the visual system is discussed.