 - MRI exclusions, including claustrophobia, cardiac pacemaker, metal fragments in eyesskinbody shrapnel, aorticaneurysm clips, prosthesis, by-pass surgerycoronary artery clips, hearing aid, heart valve replacement, shunt ventricular or spinal, electrodes, metal platespinsscrewswires, or neurobio-stimulators TENS unit, persons who have ever been a metal workerwelder, history of eye surgeryeyes washed out because of metal, women who are or may be pregnant determined by a positive pregnancy test, women using an intrauterine device, vision problems uncorrectable with lenses, inability to lie still on ones back for 60 minutes; prior neurosurgery; older tattoos with metal dyes; unwillingness to remove nose, ear, tongue or face rings. 