The daily activity rhythm of most rodents can be easily recorded because they
love nothing more than running in a wheel. Not only "bored" laboratory rodents,
living in captivity, become wheel-running junkies. The story goes that an American clock researcher stored unused running wheels from the lab in his garage. Coming home late one evening, he heard the familiar squeaky sound of
turning wheels coming from the garage and found that a family of wild mice had
adopted the garage as a workout gym.
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In fact, increased acetylation levels in the brain seem to be consistently associated with improved memory. Learning and memory both improved in mice kept in conditions known as environmentally enriched. This is a fancy way of saying they had access to two running wheels and the inside of a toilet roll.
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