- We will exclude any participant from MRI scanning procedures whose body contains a ferromagnetic implanted device that might produce a safety hazard during fMRI. We will follow guidelines found in the manual, Magnetic Resonance: Bioeffects, Safety, and Patient Management72 ,supplemented by the current information published on the International MR Safety Web Site: http://www.mrisafety.com/safety_info.asp Note: Syphilis testing will not be performed as part of this study and the study will rely solely on subjects' self report.