[1] Washington Univ, Sch Med, Dept Neurol, St Louis, MO 63110 USA
[2] Washington Univ, Sch Med, Dept Radiol, St Louis, MO 63110 USA
[3] Washington Univ, Sch Med, Dept Anat, St Louis, MO 63110 USA
[4] Washington Univ, Sch Med, Dept Neurobiol, St Louis, MO 63110 USA