The primary purpose of the study is to evaluate the effect of PF-04995274 on cerebrospinal fluid levels of soluble Amyloid precursor protein fragments and Amyloid beta fragments following single oral dose in healthy volunteers. Safety and tolerability of PF-04995274 single dose administration in healthy volunteers will also be assessed as part of the objectives.

The purpose of the study is to evaluate the effect of PF-04995274 on CSF levels of s-APP and Abeta fragments following single oral dose in healthy volunteers

Inclusion Criteria:

• For all cohorts, healthy male and/or female subjects of nonchildbearing potential between the ages of 18 and 55 years, inclusive. (Healthy is defined as no clinically relevant abnormalities identified by a detailed medical history, full physical examination, including blood pressure and heart rate measurement, 12 lead ECG and clinical laboratory tests).

Exclusion Criteria:

• Evidence or history of clinically significant hematological, renal, endocrine, pulmonary, gastrointestinal, cardiovascular, hepatic, psychiatric, neurologic, or allergic disease (including drug allergies, but excluding untreated, asymptomatic, seasonal allergies at time of dosing).
• Pregnant or nursing women; women of childbearing potential.