1. David Geffen School of Medicine, Semel Institute for Neuroscience and Human Behavior, University of California, Los Angeles, CA, USA;
2. Department of Psychology, Michigan State University, East Lansing, MI, USA;
3. Friends Research Institute, Inc., Los Angeles, CA, USA;
4. Development Core, Center for HIV Identification, Prevention, and Treatment Services, University of California, Los Angeles, CA, USA;
5. Center for HIV Identification, Prevention and Treatment Services, University of California, Los Angeles, CA, USA