 This imaging study will be an open label, non-randomised PET receptor occupancy study using healthy male volunteers. The time course and degree of D3 receptor occupancy RO after single doses of GSK618334 will be determined using 11C-PHNO as a PET ligand labeling dopamine receptor. The PKPD relationship between plasma concentrations of GSK618334 and D3 RO will be described. Potential relationships between D3 RO and functional magnetic resonance imaging fMRI endpoints will be assessed as an exploratory aim. 