1 Brain Imaging and TMS Laboratory, Department of Psychology, University of Arizona, Tucson, AZ, USA.
2 Departments of Neurology and Molecular and Cellular Biology, College of Medicine, University of Arizona, Tucson, AZ, USA; Evelyn F McKnight Brain Institute, Arizona Center on Aging, and BIO5 Institute, University of Arizona, Tucson, AZ, USA.
3 Departments of Physiology and Neuroscience, College of Medicine, University of Arizona, Tucson, AZ, USA.
4 Brain Imaging and TMS Laboratory, Department of Psychology, University of Arizona, Tucson, AZ, USA; Evelyn F McKnight Brain Institute, Arizona Center on Aging, and BIO5 Institute, University of Arizona, Tucson, AZ, USA. Electronic address: yinghuichou@arizona.edu.