bypass? >> the problem with alcoholism goes way up. the way the alcohol gets to the brain is much different. we see lots of bypass patients -- >> challenges even with depression. even when you lose 100 pounds and you think they'd really be doing well. >> absolutely. >> larry: we have a facebook question posted on our facebook page. where else would it come? do we know that part of the brain causes obsessive compulsive behavior? >> there's a lot of imaging work with obsessive compulsive. the prefrontal cortex, we've been talking about this. rather than being low, which we see in impulsive disorders, the prefrontal cortex works too hard with people with ocd. we call it hyperfrontality. some of the medicines or therapies we use actually calm down the prefrontal cortex so people don't think about things over and over again. >> we posted to the larry king facebook page asking for questions for this show on the brain. we've got a lot. don't have time to get them all in. 12 years ago, i got into an