['Two experiments were conducted to determine if dietary supplementation with Concord grape juice could reverse the latent learning impairment normally observed in middle-aged male rats.', 'Both experiments utilized the latent cue preference (LCP) task, in which water-replete rats sample water in one compartment of a three-compartment box, and are subsequently given a compartment preference test when water-deprived to determine if they remember the compartment cue previously associated with water. In the first experiment, 40 male Sprague-Dawley rats (9, 10, 11, or 12 months old) were used to determine the age of onset of the impairment. In the second experiment, 24 male Sprague-Dawley rats (11 months old) were given daily access (10 ml/day) to 50% Concord grape juice, 50% white grape juice, or a calorically-equivalent sugar solution daily for 5 weeks prior to training.', 'The first experiment revealed that the latent learning impairment begins to manifest at 10 months of age in the male rats and is fully present at 11 months. The second experiment showed that rats that consumed the 50% Concord grape juice for 5 weeks beginning at 11 months of age showed intact latent learning in the LCP task, while rats that consumed the other two supplements showed the normal impairment on the LCP task.'] Does concord grape juice reverse the age-related impairment in latent learning in rats?