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"Humans are storytelling machines. We don't passively perceive the world - we tell stories about it, translating the helter-skelter of events into tidy narratives. This is often a helpful habit, helping us make sense of mistakes, consider counterfactuals and extract a sense of meaning from the randomness of life. But our love of stories comes with a serious side-effect: like all good narrators, we tend to forsake the facts when they interfere with the plot. We're so addicted to the anecdote that we let the truth slip away until, eventually, those stories we tell again and again become exercises in pure fiction. Just the other day I learned that one of my cherished childhood tales - the time my older brother put hot peppers in my Chinese food while I was in the bathroom, thus scorching my young tongue - actually happened to my little sister. I'd stolen her trauma. The reason we're such consummate bullshitters is simple: we bullshit for each other. We tweak our stories so that they become better stories. We bend the facts so that the facts appeal to the group. Because we are social animals, our memory of the past is constantly being revised to fit social pressures. The power of this phenomenon was demonstrated in a new Science paper by Micah Edelson, Tali Sharot, Raymond Dolan and Yadin Dudai. The neuroscientists were interested in how the opinion of other people can alter our personal memories, even over a relatively short period of time. The experiment itself was straightforward. A few dozen people watched an eyewitness style documentary about a police arrest in groups of five. Three days later, the subjects returned to the lab and completed a memory test about the documentary. Four days after that, they were brought back once again and asked a variety of questions about the short movie while inside a brain scanner. This time, though, the subjects were given a "lifeline": they were shown the answers given by other people in their film-viewing g

"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."

"Virtually nobody has memories from very early childhood - but it's not because we don't retain information as young children. Rather, it may be because at that age, our brains don't yet function in a way that bundles information into the complex neural patterns that we know as memories. It's clear that young children do remember facts in the moment - such as who their parents are, or that one must say "please" before mom will give you candy. This is called "semantic memory." Until sometime between the ages two and four, however, children lack "episodic memory" -- memory regarding the details of a specific event. Such memories are stored in several parts of the brain's surface, or "cortex." For example, memory of sound is processed in the auditory cortexes, on the sides of the brain, while visual memory is managed by the visual cortex, at the back. A region of the brain called the hippocampus ties all the scattered pieces together. "

"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."