title: Long-term treatment with antioxidants and a program of behavioral enrichment reduces age-dependent impairment in discrimination and reversal learning in beagle dogs.
abstract: The effects of long-term treatment with both antioxidants and a program of behavioral enrichment were studied as part of a longitudinal investigation of cognitive aging in beagle dogs. Baseline performance on a battery of cognitive tests was used to assign 48 aged dogs (9-12 years) into four cognitively equivalent groups, of 12 animals per group: Group CC (control food-control environment), group CE (control food-enriched environment); Group AC (antioxidant fortified food-control environment); Group AE (fortified food-enriched environment). We also tested a group of young dogs fed the control food and a second group fed the fortified food. Both groups of young dogs received a program of behavioral enrichment. To evaluate the effects of the interventions on cognition after 1 year, the dogs were tested on a size discrimination learning task and subsequently on a size discrimination reversal learning task. Both tasks showed age-sensitivity, with old dogs performing more poorly than young dogs. Both tasks were also improved by both the fortified food and the behavioral enrichment. However, in both instances the treatment effects largely reflected improved performance in the combined treatment group. These results suggest that the effectiveness of antioxidants in attenuating age-dependent cognitive decline is dependent on behavioral and environmental experience.
authors.affiliation: Division of Life Sciences, University of Toronto, 1265 Military Trail, Scarborough, Ont., Canada M1C 1A4. milgram@psych.utoronto.ca
authors.forename: Norton W
authors.initials: NW
authors.lastname: Milgram
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Head
authors.forename: Steven C
authors.initials: SC
authors.lastname: Zicker
authors.forename: Candace
authors.initials: C
authors.lastname: Ikeda-Douglas
authors.forename: Heather
authors.initials: H
authors.lastname: Murphey
authors.forename: Bruce A
authors.initials: BA
authors.lastname: Muggenberg
authors.forename: Christina T
authors.initials: CT
authors.lastname: Siwak
authors.forename: P Dwight
authors.initials: PD
authors.lastname: Tapp
authors.forename: Stephen R
authors.initials: SR
authors.lastname: Lowry
authors.forename: Carl W
authors.initials: CW
authors.lastname: Cotman
mesh_terms: D000375:Aging / Q000502:physiology*; D000818:Animals; D000975:Antioxidants / Q000008:administration & dosage*; D001205:Ascorbic Acid / Q000008:administration & dosage; D001522:Behavior, Animal / Q000502:physiology*; D002331:Carnitine / Q000008:administration & dosage; D004032:Diet; D004193:Discrimination Learning / Q000502:physiology*; D004285:Dogs; D004777:Environment; D005527:Food, Fortified; D007859:Learning Disabilities / Q000503:physiopathology / Q000517:prevention & control*; D008137:Longitudinal Studies; D008954:Models, Biological; D012193:Reversal Learning / Q000502:physiology*; D008063:Thioctic Acid / Q000008:administration & dosage; D014810:Vitamin E / Q000008:administration & dosage / Q000097:blood
chemical_list: D000975:Antioxidants; D014810:Vitamin E; D008063:Thioctic Acid; D001205:Ascorbic Acid; D002331:Carnitine