What Happens to the Brain in a Collision Like That?

The first thing you get is everything starts to vibrate. And then after that initial a vibration, ihmit's almost like youre kond in a dream. It is kind of floating, and your legs are like yellow. So you pretty much as fall fla backone facing em ouch. Our brains are designed to float around inside the skull to survive the daily bumps of life. But playing football is different - it's one tough guy running full speed into another guy travelling just as fast in the opposite direction. I ask doctor canto, what can happen to the brain in a collision like that?