Summary:
- Researchers conducted a 30-year longitudinal study selectively breeding mice for high voluntary wheel-running activity, resulting in a distinct lineage of "super-athlete" mice.
- The study revealed that these high-activity mice developed significantly larger midbrains—the region associated with reward and motivation—suggesting a biological basis for the drive to exercise.
- The findings provide critical insights into the evolutionary and neurological underpinnings of physical activity, suggesting that the "urge" to be active is a heritable trait linked to specific brain morphology rather than just physical capacity.