[1] Mayo Clin, Dept Neurosci, Jacksonville, FL 32224 USA
[2] Mayo Clin, Dept Neurosci, Rochester, MN USA
[3] Kyushu Univ, Grad Sch Med Sci, Neurol Inst, Dept Neurol, Fukuoka 812, Japan
[4] Mayo Clin, Div Biostat, Dept Hlth Sci Res, Rochester, MN USA
[5] Mayo Clin, Dept Neurol, Rochester, MN USA
[6] Mayo Clin, Dept Neurol, Jacksonville, FL 32224 USA