1. From the Institute of Health and Wellbeing (D.F.M., J.P.P.), the Institute of Neuroscience and Psychology (E.R.R., W.S.), and the Institute of Cardiovascular and Medical Sciences (K.S., J.A.M.), University of Glasgow, the Hampden Sports Clinic, Hampden Stadium (K.S., J.A.M.), and the Department of Neuropathology, Queen Elizabeth University Hospital (W.S.) — all in Glasgow, United Kingdom.