SPATIAL LEARNING AND MEMORY IMPAIRMENT AFTER CENTRAL NERVOUS SYSTEM (CNS) NEONATAL IRRADIATION

PAGOTTO, R. M. L; DI TORO, P. G; ZIEHER, L. M.; GUELMAN LR

San Diego, CA, USA

Congreso; 34th Annual Meeting de la Society for Neuroscience (SFN); 2004

Society for Neuroscience (SFN)

Learning and memory have been commonly associated with hippocampal function. However, recent works have demonstrated that cerebellum could also participate in these behavioral skills. Previous data of our laboratory have shown that ionizing radiations induce cerebellar alterations. The aim of this work was to test the effect of ionizing radiation on cognitive function, being cerebellum one of the main targets of radiation-induced damage and hippocampus another structure that could potentially be affected. Neonatal rats were irradiated and at 40, 60 or 180 days post-irradiation were subjected to a spatial learning and working memory test (radial arm maze) and to a reference memory test (passive avoidance). Radiation-induced damage in cerebellum and hippocampus was monitored by measurement of an oxidative stress marker (ROS levels). Results show that irradiated rats committed more errors in the spatial memory test than control animals, in all ages studied. In addition, irradiated animals of 60 and 180 days made fewer correct choices until the first error than control animals, suggesting that neonatal ionizing radiation induced spatial learning and/or working memory impairments, which could be mainly related to cerebellar damage. No differences between control and irradiated animals were observed in the passive avoidance test, suggesting that ionizing radiation might not affect reference memory, mainly related to hippocampal function. ROS levels were unchanged when comparing control and irradiated animals at all ages tested, suggesting that radiation-induced oxidative stress damage is not temporally related to behavioral abnormalities. Supported by UBA (M040) and CONICET (PIP724) grants.