1 HudsonAlpha Institute for Biotechnology, Huntsville, AL 35806, USA.
2 Memory and Aging Center, Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA; Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA 94158, USA. Electronic address: Jennifer.Yokoyama@ucsf.edu.