IIRC, Matt Birk has already said he wants his brain studied after he dies. I don't know how many concussions he's had, but (as a center) I suspect its multiple over the course of HS, college, and a several year NFL career and he would be a good one to get a look at. From what I understand, he's not experiencing any unusual health issues and is doing well (actually lost a ton of weight and is big involved in nutrition now). It will be interesting to see what they find. Hopefully, he's got a long time left before anyone sees his results but we need more guys like that to volunteer (or their families to do so pm). And, obviously, need to see several avg Joe's (who never played contact sports) scans along with those of athletes from other sports, too.