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"MIT researchers have shown, for the first time ever, that memories are stored in specific brain cells. By triggering a small cluster of neurons, the researchers were able to force the subject to recall a specific memory. By removing these neurons, the subject would lose that memory. As you can imagine, the trick here is activating individual neurons, which are incredibly small and not really the kind of thing you can attach electrodes to. To do this, the researchers used optogenetics, a bleeding edge sphere of science that involves the genetic manipulation of cells so that they're sensitive to light. These modified cells are then triggered using lasers; you drill a hole through the subject's skull and point the laser at a small cluster of neurons. Now, just to temper your excitement, we should note that MIT's subjects in this case are mice - but it's very, very likely that the human brain functions in the same way. To perform this experiment, though, MIT had to breed genetically engineered mice with optogenetic neurons - and we're a long, long way off breeding humans with optogenetic brains. In the experiment, MIT gave mice an electric shock to create a fear memory in the hippocampus region of the brain (pictured above) - and then later, using laser light, activated the neurons where the memory was stored. The mice "quickly entered a defensive, immobile crouch," strongly suggesting the fear memory was being recalled."

"Scientists say they have found a way to activate the brain cells that trigger particular memories, according to research published today in the journal Science. Researchers at MIT employed optogenetics, a branch of science that uses light to stimulate molecules, to show that memories reside in specific brain cells, and that activating a tiny fraction of brain cells can revive the entire memory. The study was performed on mice, but the researchers say it is a powerful demonstration that memories are tangible and are physically stored in a particular part of the brain. "We demonstrate that behaviour based on high-level cognition, such as the expression of a specific memory, can be generated in a mammal by highly specific physical activation of a specific small subpopulation of brain cells, in this case by light," said Susumu Tonegawa, the Picower Professor of Biology and Neuroscience at MIT and lead author of the study. In the early 1900s, the Canadian neurosurgeon Wilder Penfield found that when he electrically stimulated certain neurons in the hippocampus area of the brain, his patients vividly recalled whole events. Until now, however, scientists have been unable to prove that the direct reactivation of the hippocampus was enough to cause memory recall."

"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."

"Scientists have for the first time recorded individual brain cells in the act of summoning a spontaneous memory, revealing not only where a remembered experience is registered but also, in part, how the brain is able to recreate it. The recordings, taken from the brains of epilepsy patients being prepared for surgery, demonstrate that these spontaneous memories reside in some of the same neurons that fired most furiously when the recalled event had been experienced. Researchers had long theorized as much but until now had only indirect evidence. Experts said the study had all but closed the case: For the brain, remembering is a lot like doing (at least in the short term, as the research says nothing about more distant memories). The experiment, being reported Friday in the journal Science, is likely to open a new avenue in the investigation of Alzheimer's disease and other forms of dementia, some experts said, as well as help explain how some memories seemingly come out of nowhere. The researchers were even able to identify specific memories in subjects a second or two before the people themselves reported having them. "This is what I would call a foundational finding," said Michael J. Kahana, a professor of psychology at the University of Pennsylvania, who was not involved in the research. "I cannot think of any recent study that's comparable. "

"A 54-year-old woman showed up in the emergency room at Georgetown University Hospital with her husband, unable to remember the past 24 hours. Her newer memories were hazy, too. One thing she did recall: Her amnesia had started right after having sex with her husband just an hour before. While sex can be forgettable or mind-blowing, for some people, it can quite literally be both at the same time. The woman, whose case was reported in the September issue of The Journal of Emergency Medicine, was experiencing transient global amnesia, a rare condition in which memory suddenly, temporarily, disappears. People with transient global amnesia suffer no side effects, and the memory problems usually reverse themselves in the span of a few hours. It's a rare condition, affecting only about 3 to 5 people per 100,000 each year. But what makes transient global amnesia so eerie is that researchers aren't sure what causes it, or why patients remain otherwise chatty and alert while missing large chunks of their memories."

"Case histories make contributions to science and practice, but they can also be highly misleading. We illustrate with our re-examination of the case of Jane Doe; she was videotaped twice, once when she was six years old and then eleven years later when she was seventeen. During the first interview she reported sexual abuse by her mother. During the second interview she apparently forgot and then remembered the sexual abuse. Jane's case has been hailed by some as the new proof of recovery of repressed or dissociated traumatic memories, and even as proof of the reliability of recovered memories of repeated abuse. Numerous pieces of "supporting evidence" were given in the original article for believing that the abuse occurred. Upon closer scrutiny, however, there are reasons to doubt not only the "supporting evidence," but also that the sexual abuse ever happened in the first place. Our analysis raises several general questions about the use of case histories in science, medicine, and mental health. There is a cautionary tale not only for those professionals who advance the case history, but also for those who base their theories on it or would readily accept it as proof."

"The scientists exchanged one last look and held their breath. Everything was ready. The electrode was in place, threaded between the two hemispheres of a living cat's brain; the instruments were tuned to pick up the chatter passing from one half to the other. The only thing left was to listen for that electronic whisper, the brain's own internal code. The amplifier hissed - the three scientists expectantly leaning closer - and out it came, loud and clear. "We all live in a yellow submarine, yellow submarine, yellow submarine ...." "The Beatles' song! We somehow picked up the frequency of a radio station," recalled Michael S. Gazzaniga, chuckling at the 45-year-old memory. "The brain's secret code. Yeah, right!" Dr. Gazzaniga, 71, now a professor of psychology at the University of California, Santa Barbara, is best known for a dazzling series of studies that revealed the brain's split personality, the division of labor between its left and right hemispheres. But he is perhaps next best known for telling stories, many of them about blown experiments, dumb questions and other blunders during his nearly half-century career at the top of his field. "

"Fear can distort our perceptions, psychological research indicates, and creepy-crawly spiders are no different. People who are afraid of spiders see the arachnids as bigger than they actually are, recent experiments have shown. Researchers asked people who had undergone therapy to address their fear of spiders to draw a line representing the length of a tarantula they had just encountered in a lab setting. "On average, the most fearful were drawing lines about 50 percent longer than the least fearful," said Michael Vasey, lead study researcher and professor of psychology at Ohio State University. "We have seen participants draw lines that are at least three times as long as the actual spider." [What Scares You? (Infographic)] After undergoing exposure therapy - in which people confront something they fear, in this case, spiders - 57 people with spider phobia were given the task of approaching a spider in an aquarium, then using a 4-inch (10.2 centimeter) probe to nudge it around the tank. They repeated this encounterfive times with different species of spider over eight weeks. "