1. Netherlands Institute for Brain Research (I.F.P., J.v.d.V., R.M.B., A.K.), 1105 AZ Amsterdam, The Netherlands
2. Human and Animal Physiology Group (I.F.P., E.M.v.d.B., H.J.M.S.), Department of Animal Sciences, Wageningen University, Wageningen 6709 PJ, The Netherlands
3. Medical Pharmacology Group (V.M.W.), Rudolf Magnus Institute for Neurosciences, University Medical Center Utrecht, Utrecht 3584 CG, The Netherlands