Veterans Affairs and Stanford University Medical Centers, Menlo Park, CA.
Send correspondence and reprint requests to Keith Humphreys, PhD, Veterans Affairs and Stanford University Medical Centers, 795 Willow Road (152-MPD), Menlo Park, CA. E-mail: [email protected]
Received 6 February, 2017
Accepted 8 February, 2017
Funding: The preparation of this paper was supported by the Stanford Neurosciences Institute and the Veterans Affairs Health Services Research and Development Service.
Conflicts of interest: The opinions expressed here are not necessarily those of any government agency that the author has worked for or advised.