[Role of the hippocampal cortex and dorsal ventricular margin in the conditioned reflex behavior of Ophisaurus apodus].

In lizards Ophisaurus apodus, extinction of the motor alimentary conditioned reflex, discrimination of location of visual signals were disturbed, and the ability for reversal of the stimuli signal significance was completely lost following bilateral ablation of dorsal parts of the hippocampal cortex. Elaboration of the motor alimentary reflex was not affected. The extent of disturbances depended on the volume of hippocampectomy. The defect resulting from the bilateral lesion of the dorsal ventricular ridge (DVR) depended on the localization of the lesion. Following lesion of the lateral part of the DVR, which is the site of thalamic visual projections, in addition to disturbances of discrimination of visual signals location and of reversal of their signal significance, elaboration of a motor alimentary conditioned reflex to the location of the signal was also affected. Following a central lesion of DVR, such disturbances were less pronounced, while with medial lesions there were practically none. A conclusion has been made that disturbances of conditioned reflexes due to hippocampectomy and DVR damage, differ in their manifestation and nature: the former are similar to the defect after hippocampectomy in mammals and are, perhaps to the disturbance of the inhibition function, while the latter are primarily due to disturbance of the visual function.