clean your brain and slow down dementia. they conclude sleep gets rid of the gunk that builds up in our brains when we re awake and may be critical in the treatment of people with alzheimer s and other mind disorders. people who didn t get enough sleep had trouble with reaction time. thank you, michaela. you re welcome. check this out, a 200 million-year-old boulder at the center of a criminal investigation. three guys pushed over the boulder. an investigation is now under way. it starts like an ordinary tourist video, three boy scout leaders posing alongside a 200 million-year-old rock in utah. one of them starts to wiggle it. wiggle it just a little bit. [ laughter ] but it s no laughing matter. these men could face felony charges for toppling that ancient rock. the sand stone boulders date