A new study shows playing just one season of college football can harm a player’s brain, even if they don’t receive a concussion. Although only two of the 38 players received a concussion, more than two-thirds of them showed changes to the integrity of the white matter of their midbrains. Rotational hits—when a player’s helmet is struck by a glancing blow—were particularly bad for the midbrain’s white matter, the team reports today in Science Advances. Researchers followed 38 football players. The athletes wore helmets outfitted with accelerometers to track the number and force of hits during practices and games. Before and after each season, the scientists took MRI scans of the players’ brains. The researchers looked specifically at the midbrain, a region on the brain stem that governs primitive, thoughtless functions such as hearing and temperature regulation. Although the forces can affect many regions of the brain, the midbrain’s central location makes it likely to sustain damage.
The midbrain is like the “canary in the coal mine for the whole brain,” says study author Bradford Mahon, a neuroscientist at Carnegie Mellon University. Mahon and Hirad hope the region will prove useful to doctors and researchers in the future, and show a more nuanced picture of how football’s repetitive hits can harm players’ brains, even when they are not concussed.