[1] Vet Affairs Med Ctr, Serv Neurol, Neurol Res Labs, Ann Arbor, MI 48105 USA
[2] Univ Michigan, Dept Neurol, Ann Arbor, MI 48109 USA
[3] Univ Michigan, Dept Physiol, Ann Arbor, MI 48109 USA
[4] Univ Michigan, Dept Psychiat, Ann Arbor, MI 48109 USA
[5] Univ Michigan, Dept Internal Med, Ann Arbor, MI 48109 USA
[6] Univ Michigan, Dept Biostat, Ann Arbor, MI 48109 USA
[7] Aalborg Univ, Ctr Sensory Motor Interact, DK-9220 Aalborg, Denmark