1. Department of Physiology, University of California, Los Angeles, Los Angeles, CA 90095-1751, USA.
2. Department of Neurology, University of California, Los Angeles, Los Angeles, CA 90095-1751, USA.
3. Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, Los Angeles, CA 90095-1751, USA.
4. Center for Neurobehavioral Genetics, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095-1751, USA.
5. Department of Neurobiology, University of California, Los Angeles, Los Angeles, CA 90095-1751, USA.