A Study of Healthy Subjects to Assess the Effect of LY450139 on Amyloid Beta Peptide Production Rate and or Dose Response.

Inclusion Criteria: * Healthy volunteers: Men within the ages of 21 and 50 Exclusion Criteria: * Have serious or unstable medical conditions * Have a history of serious infections affecting the brain or head trauma resulting in protracted loss of consciousness within the last 5 years or multiple episodes of head trauma * Have a history of primary or recurrent malignant disease * Have a recent laboratory result indicating a clinically significant laboratory abnormality as determined by the investigator * Have a history of chronic alcohol or drug abuse within the past 5 years * Have a known history of Human immunodeficiency virus (HIV), afebrile seizures, or clinically significant multiple drug allergies * Are judged clinically by the investigator to be at serious risk for suicide * Have electrocardiogram abnormalities obtained at visit 1 that in the opinion of the investigator are clinically significant * Use of prescription or over the counter medications that cannot safely be discontinued within 14 days prior to visit 2 * Have criteria that would preclude a LP such as allergy to all local anesthetics; have a local infection at the site of the LP or have any medical condition requiring treatment with warfarin or heparin. * Have received treatment within the last 30 days with a drug that has not received regulatory approval for any indication at the time of study entry. * Are investigator site personnel directly affiliated with this study and or immediate families. * Are Lilly employees