(Portland, OR)  --  Researchers at Oregon Health & Science University are unveiling a new study that shows how space affects the brains of new astronauts.  The researchers took MRIs of new astronauts after they returned to Earth and found the area around blood vessels increased in size.  However, the change didn't continue for astronauts who made additional trips to space.  There were no neurological problems with balance or memories.  The increase is seen in people who are older and people with dementia.  The study could help diagnose and treat diseases that affect circulation in the brain.