ORG 2766 fails to improve visual functions in rats with occipital lesions

Adult rats were trained on a white versus black card discrimination in a circular water tank. Three independent variables were manipulated: lesion (sham, lateral occipital, medial occipital), dose of ORG 2766 administered (0 or 25 micrograms in saline on alternate days for 18 days), and time of administration (during the post-surgical recovery interval or during post-operative testing). Both visual cortical lesions produced a prominent retention deficit and defective pattern vision. Neither post-surgical nor concurrent administration of ORG 2766 improved visual functions. These results, along with a growing body of evidence, challenge the generality of the positive influences of ORG 2766 upon behavioral recovery observed in animals with limbic lesions.