1. Department of Neufoscience, Karolinska Institutet (KI), SE-171 77 Stockholm, Sweden
2. Agora for Biosystems, P.O. Box 57, SE-193 22 Sigtuna, Sweden
3. Institute of Physiology, Deutschhausstr. 2, D-35037 Marburg, Germany
4. Dept. of Psychiatry and Psychotherapy, Philipps-University Marburg, Rudolf - Bultmannstraße 8, D-35033 Marburg, Germany
5. Dept. of Biometry and Engineering, SLU, P.O. Box 7032, SE-750 07 Uppsala, Sweden