Oculomotor cortex localization in the unanesthetized cat.

In recent years two of us have investigated the neural structure of the visual fixation reflex in the cat (Dreher et al. 1965, Dreher and i e r nicki 1969ab). In these studies we were interested in the effects of ablfation of cortical oculomotor areas. However, available data in the localination of these areas are not adequate. In anesthetized cats relatively small cortical ocu~lomotor areas were described (Gar01 1942, Shipova 1965). We know, however, that the oculomotor effects of cortical stimulation may be affected by the narcosis (Krieger et lal. 1958). Small oculomotor areas were also observed by Claes (1939) in the enckphale is016 cats. On the contrary, some data obtained in the intact freely moving cats suggest that the cortical oculomotor areas are very large (Fangel and Kaada 1960). The objective of this paper was to complete the data concerning the localization of the oculomotor cortex in the cat. For this purpose the pretrigeminal preparation was used (Batini el al. 1959, Zernicki 1968). A well-known drawback of this preparation is that only vertical eye movements are controlled by the isolated cerebrum. However, due to the pretrigeminal transection the pain factor is eliminated and consequently neither the narcosis nor local anesthesia necessary.