[1] Scripps Res Inst, Dept Mol & Expt Med, La Jolla, CA 92037 USA
[2] Univ Calif Irvine, Dept Neurol, Irvine, CA 92717 USA
[3] Univ Calif Irvine, Dept Anat & Neurobiol, Irvine, CA 92717 USA
[4] Univ So Calif, Keck Sch Med, Dept Prevent Med, Los Angeles, CA 90033 USA