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"Researchers led by New York University neuroscientist Joseph LeDoux recently claimed to be the first scientists to erase a single memory. Working with rats, LeDoux's team first taught the animals to fear both a beep and a siren by giving them an electric shock every time either of the tones sounded. Then LeDoux gave half the rats the drug U0126, which is known to interfere with memory storage, and replayed the beep without electric shocks. A day later, when LeDoux played back both tones to the rats, the animals that hadn't been given the drug were still fearful of both sounds. But the rats that had been given the memory-blocking drug weren't afraid of the beep, which they had last heard while under the influence of U0126. advertisement | article continues below Click here! Exactly how U0126 exerts its amnesiac effect is unknown, but it may block the synthesis of proteins that help strengthen connections between neurons and establish memories. The opportunity for erasure occurs during the act of retrieving a memory because that's when the memory is being updated and stabilized again for long-term storage. "Only those memories that are activated are vulnerable," LeDoux says. Drugs like U0126 may someday help sufferers of traumatic memories. A small group of human studies have been done on a drug called propranolol, which blocks the action of stress neurotransmitters that help cement memories in the brain, but LeDoux's work shows the potential for greater precision. "You might be able to reduce the traumatic impact of memories in people with PTSD," says LeDoux. "The good news is you wouldn't be erasing their memory bank." "

"In my article in the last issue, I focused mainly on the recent books by psychologist Irving Kirsch and journalist Robert Whitaker, and what they tell us about the epidemic of mental illness and the drugs used to treat it.1 Here I discuss the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders (DSM)-often referred to as the bible of psychiatry, and now heading for its fifth edition-and its extraordinary influence within American society. I also examine Unhinged, the recent book by Daniel Carlat, a psychiatrist, who provides a disillusioned insider's view of the psychiatric profession. And I discuss the widespread use of psychoactive drugs in children, and the baleful influence of the pharmaceutical industry on the practice of psychiatry. One of the leaders of modern psychiatry, Leon Eisenberg, a professor at Johns Hopkins and then Harvard Medical School, who was among the first to study the effects of stimulants on attention deficit disorder in children, wrote that American psychiatry in the late twentieth century moved from a state of "brainlessness" to one of "mindlessness."2 By that he meant that before psychoactive drugs (drugs that affect the mental state) were introduced, the profession had little interest in neurotransmitters or any other aspect of the physical brain. Instead, it subscribed to the Freudian view that mental illness had its roots in unconscious conflicts, usually originating in childhood, that affected the mind as though it were separate from the brain. But with the introduction of psychoactive drugs in the 1950s, and sharply accelerating in the 1980s, the focus shifted to the brain. Psychiatrists began to refer to themselves as psychopharmacologists, and they had less and less interest in exploring the life stories of their patients. Their main concern was to eliminate or reduce symptoms by treating sufferers with drugs that would alter brain function. An early advocate of this biological

"Recall a time you said or did something incorrect in front of peers or authority figures. Now think of all the details you can recall associated with that experience. Where you were, who was there, any other things you wouldn't ordinarily remember about distant events such as what you wore, saw, did earlier or later that day. If you have a minute, write down some of these ancillary sensory memories. What you recall now is the result of your dopamine-reward network and your flashbulb memory or event memory system. As the brain evolved for survival of the animal and the species, much of what we humans now do is directed by hard-wired neural networks and neurotransmitters not under conscious control. Actually only about 17% of your brain is capable of responding to your conscious will; the rest is pretty much like that of a lower mammal or newborn baby with reactions to input based on association with imminent danger, risk, or pleasure."

"rom heroin and cocaine to sex and lies, Tetris and the ponies, the spectrum of human addictions is vast. But for Dr. Nora D. Volkow, the neuroscientist in charge of the National Institute on Drug Abuse, they all boil down to pretty much the same thing. She must say it a dozen times a day: Addiction is all about the dopamine. The pleasure, pain and devilish problem of control are simply the detritus left by waves of this little molecule surging and retreating deep in the brain. A driven worker with a colorful family history and a bad chocolate problem of her own, Dr. Volkow (pronounced VOHL-kuv), 55, has devoted her career to studying this chemical tide. And now, eight years into her tenure at the institute, the pace of addiction research is accelerating, propelled by a nationwide emergency that has sent her agency, with a $1.09 billion budget, into crisis mode. The toll from soaring rates of prescription drug abuse, including both psychiatric medications and drugs for pain, has begun to dwarf that of the usual illegal culprits. Hospitalizations related to prescription drugs are up fivefold in the last decade, and overdose deaths up fourfold. More high school seniors report recreational use of tranquilizers or prescription narcotics, like OxyContin and Vicodin, than heroin and cocaine combined. The numbers have alarmed drug policy experts, their foreboding heightened by the realization that the usual regulatory tools may be relatively unhelpful in this new crisis. As Dr. Volkow said to a group of drug experts convened by the surgeon general last month to discuss the problem, "In the past, when we have addressed the issue of controlled substances, illicit or licit, we have been addressing drugs that we could remove from the earth and no one would suffer." But prescription drugs, she continued, have a double life: They are lifesaving yet every bit as dangerous as banned substances. "The challenges we face are much more complex," Dr. Volkow said, "becau

""Bet you can't eat just one" (as the old potato-chip commercials had it) is, of course, a bet most of us end up losing. But why? Is it simple lack of willpower that makes fatty snacks irresistible, or are deeper biological forces at work? Some intriguing new research suggests the latter. Scientists in California and Italy reported last week that in rats given fatty foods, the body immediately began to release natural marijuanalike chemicals in the gut that kept them craving more. The findings are among several recent studies that add new complexity to the obesity debate, suggesting that certain foods set off powerful chemical reactions in the body and the brain. Yes, it's still true that people gain weight because they eat more calories than they burn. But those compulsions may stem from biological systems over which the individual has no control."