1. Massachusetts General Hospital, Charlestown, MA 02129, USA, 2Bender Institute of Neuroimaging, Justus-Liebig Universität Giessen, 35394 Giessen, Germany, 3University of Massachusetts Medical School, Worcester, MA 01605, 4Massachusetts General Hospital, Boston, MA 02114 and 5Abbott Northwestern Hospital, Penny George Institute for Health and Healing, Minneapolis, MN 55407, USA, 6Benson-Henry Institute for Mind Body Medicine at Massachusetts General Hospital, Boston, MA 02114, USA