Explaining concussionsDr. Sanjay Gupta explains the physiology of concussions and the long-term effects of suffering one.SI Staff|Share on FacebookShare on XAdd us as a preferred sourceDr. Sanjay Gupta explains the physiology of concussions and the long-term effects of suffering one.Loading recommendations... Please wait while we load personalized content recommendationsPublished May 7, 2012 | Modified May 7, 2012SI STAFFShare on FacebookShare on XHome/NFL