The primary objective of the study is to evaluate the safety and tolerability of single dose of BIIB033 administered to healthy adult volunteers.

BIIB033 is an investigational product being developed to promote remyelination in subjects with multiple sclerosis (MS). This healthy volunteer study will evaluate safety and tolerability of a single dose of BIIB033.

Inclusion Criteria:

• Must be in good health
• BMI of 18-30kg/m2
• Contraception required for at least 6 months after study drug administration

Exclusion Criteria:

• History of clinically significant disease or lab values
• Females of childbearing potentials
• Contraindication to brain MRI and/or lumbar puncture
• Treatment with any prescription medication within the 28 days prior to study entry
• Treatment with any over-the-counter products, including herbal and/or alternative health preparations and procedures within the 14 days prior to study entry
• Regular use of any tobacco product within 3 months prior to study entry