Roundtable: What do video games do to our brains?

Hours spent looking at a screen, manipulating a virtual world with your fingers and thumbs - good or bad for you? Does it change your mind for better or worse? What does gaming do to us? Parents who raised a virtual child and let their own starve to death in South Korea. A teenager in the US who killed his parents because he didn't think they would be dead forever. Just two terrible events some have blamed on gaming addiction. But does such a thing even exist?