1. Neuroscience Program, W080 Clark Center, 318 Campus Drive West, Stanford University, Stanford, CA 94305, USA.
2. Department of Bioengineering, W083 Clark Center, 318 Campus Drive West, Stanford University, Stanford, CA 94305, USA.
3. Department of Psychiatry and Behavioral Sciences, W083 Clark Center, 318 Campus Drive West, Stanford University, Stanford, CA 94305, USA.
4. Ernest Gallo Clinic and Research Center, Department of Neurology, Wheeler Center for the Neurobiology of Drug Addiction, University of California San Francisco, San Francisco, CA 94158, USA.