[1] NHS Lothian, Royal Infirm Edinburgh, Edinburgh, Midlothian, Scotland
[2] Newcastle Univ, Inst Ageing & Hlth, Newcastle Upon Tyne, Tyne & Wear, England
[3] GlaxoSmithKline R&D, Stevenage, Herts, England
[4] GlaxoSmithKline R&D, Res Triangle Pk, NC USA
[5] GlaxoSmithKline, Cambridge, England
[6] Uppsala Univ, Dept Med Sci, Uppsala, Sweden
[7] Uppsala Univ, Dept Neurosci, Neurol, Uppsala, Sweden
[8] Newcastle Univ, Inst Neurosci, Newcastle Upon Tyne, Tyne & Wear, England