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Working at Scientific American , known for its spiffy technical illustrations, I always look formaterial that can show what an article is trying to tell.I"ve never found a better example than this video(below) of arat fed a drug that wipes out its long-term memory, and which bearsa real-life resemblance to the scenario depicted in "EternalSunshine of the Spotless Mind." The opening paragraphs of thearticle by Jerry Adler, called " Erasing Painful Memories ." serves as a running narrative to the video. I"ve includedthem here: The rat is on a carousel with clear plastic sides, rotating slowlyin a small room. As it looks out through the plastic, it seesmarkings on the walls of the room from which it can determine itsposition. At a certain location it receives a foot shock—or,in experimenters" jargon, a negative reinforcement. When thathappens, the rat turns sharply around and walks tirelessly in theopposite direction, so it never reaches that same place in the roomagain. It will do this to the point of exhaustion. Question: How do you get the rat to stop walking? Note that just turning off the shock will not suffice, because therat will not allow itself to enter the danger zone. The rat needsan intervention that helps it forget its fear or that overrides itsresponse with a competing signal of safety. So much for the rat.Now think of someone who has been wounded in combat and suffersfrom the vague but real cluster of symptoms called post-traumatic stress disorder ( PTSD ). He, too, associates specific contexts or stimuli—openspaces, crowds, sudden loud noises—with something painful. He avoids those circumstances when he can. He is in the same bindas the rat on the turntable: unable to discover for himself thatcertain situations are now safe. How do we get him to stop running?The rat on the carousel and the veteran on a crowded street areboth prisoners of the extraordinary power of pain to forge an indelible impression on the brain: be it mammalian,reptile or even invertebrate. The rat on the carousel and the veteran on a crowded street areboth prisoners of memory, of the extraordinary power of pain toforge an indelible impression on the brain: be it mammalian,reptile or even invertebrate. As some researchers labor to solvethe mystery of memory loss in dementia, others are attacking themirror image problem of how to help patients escape the painfulmemories that dominate their daily life—and not just thosewith PTSD. An emerging new paradigm views such diverse conditionsas phobias, obsessive- compulsive disorder, and even addiction andintractable pain as disorders of learning and memory or, morepointedly, forgetting. Some people never forget the time a spider fell into their glass ofmilk. Others cannot break the association of certain places orsituations with getting high. Now researchers are finding thatremembering is not just a process of passively storing impressions.It is a continuous, dynamic activity on the cellular level and anongoing psychological process open to manipulation with drugs andcognitive therapy. This is wonderful news for combat veterans andvictims of assaults and accidents. What it means for futuregenerations of historians and personal-injury lawyers remains to beseen. For the rat on the carousel, you can imagine different approachesto extinguishing its fear. You could let it walk to exhaustion andlearn for itself that the shock has been turned off—a processpsychologists call extinction. Or you could try tinkering directlywith the rat"s brain—specifically, the hippocampus,where place memories are formed and stored. Six years agoneuroscientist Todd Sacktor of S.U.N.Y. Downstate Medical Center inBrooklyn, building on work with his former colleague Andre Fenton,did just that. He injected a compound called ZIP into thehippocampus of a rat that had been trained onthe carousel and,after two hours, tested it again and found the fear had beenerased. Do that in a combat veteran disabled by PTSD, and you areon the way to a Nobel Prize or a billion-dollar drug bonanza. The article then goes on to explain other approaches thatresearchers are undertaking to help people forget or dull badmemories. Adler"s introduction serves as a generaldescription of the video. The specific component segments are: Pretraining: The rat, in this video playing at five times normal speed, getsused to life on the carousel. Note the unactivated, pie-shaped areaused to deliver a shock. Training Trial 8 (shock on): Now the shock is turned on, and the rat steers well clear of thedemarcated red slice. One-day retention: saline-injected rat (shock off): A day later, a rat injected with harmless saline remembers theaversive shock, steering clear of the triangular zone. One-day retention: ZIP-injected rat (shock off): The rat that has ZIP injected into its brain wanders freely thebreadth of the carousel without any memory of having been shocked. Pretraining vs. One-day retention: (Zip- Injected): A side-by-side comparison shows that the Zip-injected rat behavesexactly as it did before it received the first shock. We are high quality suppliers, our products such as Fashion Wheelchairs , China Reclining Wheel Chair for oversee buyer. To know more, please visits Reclining Wheel Chair.
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