To find out, researchers at the University of California, Riverside performed laboratory experiments on house mice and found that mice that have been bred for dozens of generations to be more exercise-loving have larger midbrains than those that have not been selectively bred this way.
Theodore Garland’s lab measured the brain mass of these uniquely athletic house mice, bred for high voluntary wheel-running, and analyzed their high-resolution brain images. The researchers found that the volume of the midbrain — a small region of the brain that relays information for the visual, auditory, and motor systems — in the bred-for-athleticism mice was nearly 13 percent larger than the midbrain volume in the control or “regular” mice.
“To our knowledge, this is the first example in which selection for a particular mammalian behavior — high voluntary wheel running in house mice in our set of experiments — has been shown to result in a change in size of a specific brain region,” said Garland, a professor of biology and the principal investigator of the research project.
Study results appeared online Jan. 16 in The Journal of Experimental Biology