BEHAVIORAL DEFICITS REVEALED BY MULTIPLE TESTS IN RATS WITH ISCHEMIC DAMAGE LIMITED TO HALF OF THE CA1 SECTOR OF THE HIPPOCAMPUS

Ischemia causes neuronal necrosis in the septal half of the CA1 sector of the hippocampus in rats and produces deficits in spatial and other tasks, but the impairments are not severe. CA1-damaged rats may perfo rm at control levels on some tests and may overlap the performance of control animals on other tests. The present study examined the perform ance of CA1-damaged rats on a range of tests known to be sensitive to hippocampal damage and evaluated the size of the deficit using a compo site test-battery score. The rats with CA1 damage were impaired on lea rning set, matching to place, and latent-learning spatial navigation i n a swimming pool, delayed alternation, and pattern alternation on dry land, but not on amphetamine-induced locomotion or on negative patter ning. The CA1-damaged rats' impairments were mild, characterized by be havioral strategies similar to those of control rats, and their test s cores overlapped those of control rats. Nevertheless, a composite prof ile derived from the measures obtained from the different tests reveal ed a large overall impairment. The results confirm that rats with part ial damage to CA1 display impairments, especially on tests that demand working memory, and suggest that the test-battery approach can be use d to enhance group differences.