1. Introduction Mary M. Torregrossa 2. Animal Models of Addiction Rita A. Fuchs 3. Transcriptional and Epigenetic Regulation of Reward Circuitry in Drug Addiction A.J. Robison 4. Neural Circuit Alterations in Addiction Matt Hearing and Eden Marie Anderson 5. Glutamatergic Neuroplasticity in Addiction L. A. Knackstedt and Allison Bechard 6. Neural Ensemble Encoding of Addictive Behavior Bruce Hope 7. Interoceptive Stimulus Effects of Drugs of Abuse Jennifer Murray 8. Maladaptive Memory Mechanisms in Addiction and Relapse Mary M. Torregrossa 9. Neural Morphology and Addiction Patrick Mulholland 10. Mechanisms regulating compulsive drug behaviors David M. Dietz 11. Role of Stress-Associated Signaling in Addiction John Mantsch and Elizabeth M. Doncheck 12. Negative Reinforcement Mechanisms in Addiction Olivier George 13. Circadian Rhythms and Addiction Ryan Logan 14. Role of Oxytocin in Countering Addiction-Associated Behaviors Exacerbated by Stress Jacqueline McGinty 15. The Role of Norepinephrine in Addiction: Past, Present, and Future David Weinshenker 16. Glial Dysregulation in Addiction David Baker 17. Role of the Extracellular Matrix in Addiction Peter W. Kalivas and Lauren Beloate 18. Striatal cell-type specific plasticity in addiction Mary Kay Lobo 19. Harnessing Circuits for the Treatment of Addictive Disorders Christelle Baunez 20. Conclusions and Future Directions Mary M. Torregrossa