On this edition of ST, we speak with two faculty members here at the University of Tulsa who are among the authors of an important new research study which appeared last week in The Journal of the American Medical Association. Dr. Patrick Bellgowan --- the lead researcher for this study, who actually first spoke with us about it last year (as it was still in progress) --- is on TU's Faculty of Community Medicine and also works at the Laureate Institute for Brain Research (or LIBR) in Tulsa, while Prof. David Polanski is the Head Trainer in TU's Department of Athletics. Their study --- entitled "Relationship of Collegiate Football Experience and Concussion with Hippocampal Volume and Cognitive Outcomes" (and accessible online here) --- is thought to be the most comprehensive research study ever to assess the effects of playing football specifically on college players. As per this summary of the study from a news post at TU's website: "College football players with and without a history of concussions have less volume in the hippocampal region of the brain that relates to memory and emotion.... Moreover, the number of years of playing experience was inversely related to hippocampal volume and reaction time." Dr. Bellgowan and Prof. Polanski expand on their findings on our program today, explaining how exactly this study was conducted, why it was done in the first place, what it demonstrates, and what it doesn't demonstrate. Our guests are quick to point out that their study does not show a causal relationship between playing contact sports and experiencing brain injury. "It's a correlation [between playing football and having smaller hippocampi]," says Dr. Bellgowan, "but we cannot infer that football has caused this correlation."