[1] Mayo Clin, Dept Neurol, Rochester, MN 55905 USA
[2] Mayo Clin, Dept Biochem & Mol Biol, Rochester, MN 55905 USA
[3] Indiana Univ Sch Med, Dept Anat Cell Biol & Physiol, Indianapolis, IN 46202 USA
[4] Univ Alberta, Dept Med, Div Neurol, Edmonton, AB T6G 2G3, Canada
[5] Mayo Clin, Dept Quantitat Hlth Sci Res, Div Comp Biol, Rochester, MN 55905 USA