the first time you met staff sergeant aaron potter, what did you see? what was going on with the staff sergeant. >> some of the things that he was having to deal with were making it difficult for him to do his job well. so it was really a time for us to come together and say, hey, look, we can help, we can make a difference here. >> step into the machine, facing the screen, we'll get you all hooked up. >> lou do you exercise the injured parts of your brain? here there are exercises for balance, puzzles for concentration and video games to teach relaxation. a treatment that can help for those suffering any type of brain injury. a sports injury, a car accident or a gunshot. the doctor says he would like to see this comprehensive approach migrate through civilian care. not just in major metropolitan trauma centers, he thinks there may be other implications for treating brain disorders. >> can you retrain a brain that may be suffering from alzheimer's or parkinson's? >> we believe you can, barbara. and you do that by exercising the part of the brain which i

aaron? >> all right. thanks a lot, tom. >> okay. >>> still ahead on "news 4 midday," we have seen him grow up on the big screen in the harry potter films. now the actor is admitting to breaking a dangerous habit. >>> and spider bites, most are harmless, but there are dangers you need to be aware of. @@@@@@ú@ >>> together! >> harry potter start daniel radcliffe says no more drinking alcohol. the 21-year-old says he started drinking heavily while filming the sixth harry potter film in 2009 and even became dependent on it to have a good time. he says instead of cutting out, he cut it out altogether, preferring to stay home and read a book. the saga of harry potter ends on thursday with the worldwide premiere of "harry potter and the deathly hallows" part 2, the final movie in the series. >>> thousands of people packed the national mall to watch the firework s spectacular. several celebrities were there to help with the celebration. dozens of actors and musicians took part in the annual capitol 4th concert in the north lawn of the capitol. ♪ good golly, miss molly >> jimmy smits hosted the event, which also featured preferences from