VALIDATION OF A SINGLE-DAY MORRIS WATER MAZE PROCEDURE USED TO ASSESSCOGNITIVE DEFICITS ASSOCIATED WITH BRAIN-DAMAGE

This experiment was designed to validate a singleday Morris Water Maze procedure used to assess cognitive functioning in rats. Separate grou ps of randomly assigned rats received either bilateral or unilateral f imbria fornix transections, bilateral or unilateral cortical ablations , or a sham surgical control procedure. Subjects were tested 7 days po stoperatively with a modified version of the Morris Water Maze procedu re that requires only a single day of training. The results indicated that bilateral fimbria fornix transections severely disrupted acquisit ion. Unilateral fimbria fornix transections and bilateral and unilater al cortical lesions disrupted acquisition less severely but impaired s ubsequent test performance. In general, unilateral lesions of both typ es produced less severe deficits than bilateral lesions. The practical and analytical advantages of the singleday procedure are discussed.