aGlaxoSmithKline, Addenbrooke’s Centre for Clinical Investigation, Cambridge CB2 2GG, UK
bDepartment of Neural and Pain Sciences, Dental School and Program in Neuroscience, University of Maryland, Baltimore, MD 21201, USA
cUniversity of Michigan and VA Medical Center, Ann Arbor, MI 48109, USA
dPain Research Center, Anesthesia Department, Stanford University, Stanford, CA 94305 and LASMED LLC, Mountain View, CA 94043, USA
eDepartment of Neurophysiology, Center for Biomedicine and Medical Technology Mannheim (CBTM), University of Heidelberg, D-68167 Mannheim, Germany
*Corresponding author. Tel.: +44 1223 296048; fax: +44 1223 296063.
Submitted July 1, 2008; revised September 2, 2008; accepted September 19, 2008.