 This is an open label, single dose, non-randomized PET study in healthy male subjects to ascertain if GSK1034702 is crossing the blood-brain barrier to enable it to elicit a central effect. GSK1034702 has been shown in vitro to be a substrate for human Pgp, therefore the distribution of GSK1034702 into human brain could be adversely affected. This use of PET in conjunction with radioactively labelled GSK1034702 will help ascertain the role Pgp plays in limiting brain penetration in the presence and absence of a pharmacological relevant oral non labelled dose of 5 mg. Subjects will have an MRI scan to aid definition of brain anatomy, a baseline PET scan and a post-dose PET scan. For each subject the study will consist of at least three visits; screening visit, scanning day and follow-up. 