egree from Pennsylvania State University and his Ph.D. in Behavioral Physiology from The Johns Hopkins University. Dr. Koob’s research interests are directed at the neurobiology of emotion, with a focus on the theoretical constructs of reward and stress. He has made contributions to our understanding of the anatomical connections of the emotional systems and the neurochemistry of emotional function. Dr. Koob has identified afferent and efferent connections of the basal forebrain in the region of the nucleus accumbens, bed nucleus of the stria terminalis, and central nucleus of the amygdala in motor activation, reinforcement mechanisms, behavioral responses to stress, drug self-administration, and the neuroadaptation associated with drug dependence. Dr. Koob also is one of the world’s authorities on the neurobiology of drug addiction. He has contributed to our understanding of the neurocircuitry associated with the acute reinforcing effects of drugs of abuse and more recently on the neuroadaptations of these reward circuits associated with the transition to dependence. He has validated key animal models for dependence associated with drugs of abuse and has begun to explore a key role of anti-reward systems in the development of dependence.
Dr. Michel LeMoal is a graduate of Herricks High School in New Hyde Park, New York. He received his B.A., his Ph.D. and his M.D. from Yale University. He completed his residency in psychiatry at both McLean Hospital in Massachusetts and Yale in 1987. Dr. LeMoal is currently the Dean for Academic and Scientific Affairs and Director of the Friedman Brain Institute at the Icahn School of Medicine at Mount Sinai in New York. Dr. LeMoal served as the Director of the Division of Molecular Psychiatry at Yale until 2000, and as Chairman of the Department of Psychiatry at the University of Texas Southwestern Medical Center at Dallas. He joined Mount Sinai in 2008. He has served on the Board of Scientific Counselors of the National Institute on Drug Abuse, on the National Advisory Mental Health Council for the National Institute of Mental Health, the National Advisory Drug Abuse Council for the National Institute on Drug Abuse, as Council Member of the American College of Neuropsychopharmacology (for which he served as president in 2011) and the Society for Neuroscience. His focus in neuropsychopharmacology concentrates on forming a molecular approach to psychiatry and furthering the understanding of the molecular basis of both depression and drug addiction, using animal models to study the way that drug use or stress affects the brain.
The main theme of this article is drug addiction and how it affects the human brain. The signs of a drug addiction consist of a high craving of drugs with no regard for the way in which it is acquired (Koob & LeMoal, p. 3115). Most of the effects of drugs occur in the brain, where it increases the level of dopamine at a specific site, often giving the user a feeling of pleasure (Koob & LeMoal, p. 3115). Almost all illicit drugs directly affect the frontal cortex of the brain, in ways in which it can lead to psychological cravings (Koob & LeMoal, p. 3116). As a result, this often causes the user to binge use. During the early stages of rehabilitation, it is often necessary for the user to take prescription medication in order to deactivate the psychological symptoms of withdrawal (Koob & LeMoal, p. 3116). There are many biological factors that are involved with the addicted brain. The addicted brain is distinctly different from the non-addicted brain, as manifested by changes in brain metabolic activity, receptor availability, gene expression, and responsiveness to environmental cues (Koob & LeMoal, pp. 3117-3118). In the brain, there are many changes that take place when drugs enter a person’s blood stream. Drug ingestion begins in the ventral tegmentum, then it goes to the nucleus accumbens, the limbic system, finally to the orbitofrontal cortex, also known as the mesolimbic reward system (Koob ; LeMoal, p. 3118). The activation of this reward system seems to be the common element in what hooks drug users on drugs.
Drugs seem to cause surges in dopamine neurotransmitters and other pleasure brain messengers. However, the brain quickly adapts and these circuits desensitize, which allows