Running Wheels and Toys Improve Memory of Aging Mice

Elderly female mice who spent three hours a day racing on running wheels and playing with rodent toys showed a marked improvement in their spatial memory, according to researchers at Yale.

The study to be published in the July/August issue of the journal Neurobiology of Aging found that the older mice who engaged in “environmental enrichment” also had increased synaptic protein levels in brain regions critical for spatial memory.

Karyn Frick, assistant professor in the Department of Psychology and lead author of the study, said she conducted the research because the majority of environmental enrichment studies in aging rodents have utilized males as their subjects. Therefore, it was not known whether females would also benefit from this simple behavioral therapy. Old mice in the study were 27 to 28-months-old, or the equivalent of about 85 in human years. The test mice were measured against four-month-old mice and elderly mice who did not play.

After two weeks, the mice were tested in the Morris water maze, a task that measures spatial memory and which requires the mice to navigate around a large pool of water to find a submerged escape platform. The elderly mice who were not exposed to environmental enrichment were clearly impaired when compared to the young mice. In contrast, the elderly mice who did play had memory capability comparable to the younger mice.

Frick and her co-author, Stephanie Fernandez, then looked at the brains of the animals – particularly the cerebral cortex and hippocampus – and found the mice exposed to environmental enrichment had significantly higher synaptic protein levels.

“These data suggest that environmental enrichment can be a potent cognitive enhancer for aged females and suggests a potential neurobiological mechanism of this effect,” Frick said.