Scientists concluded from a study sponsored by the National Institute of Aging that senior dogs are better able to learn new commands if given regular exercise and a diet fortified with vitamins, fruits, and vegetables.

Beagles given either the fortified diet, regular exercise or both did much better in learning new tricks than dogs fed regular chow and allowed to lie around more, the researchers reported on Tuesday.

The study also showed that dogs can can develop memory and learning problems as they get older in much the same way people do.

"The combination of an antioxidant diet and lots of cognitive stimulation -- which was almost the equivalent of going to school every day -- really did improve brain function in these animals," says Elizabeth Head of the University of California Irvine, who worked on the study.