[1] MRC, Inst Hearing Res, Nottingham NG7 2RD, England
[2] Forschungszentrum Julich, Dept Med INB 3, Res Ctr, Cognit Neurol Sect,Inst Neurosci & Biophys, D-5170 Julich, Germany
[3] Univ Nottingham, Sch Biomed Sci, Nottingham NG7 2RD, England
[4] Forschungszentrum Julich, Res Ctr, Brain Imaging Ctr W, D-5170 Julich, Germany
[5] Univ Hosp Koln, Dept Neurol, Cologne, Germany