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Why can we remember someone we met once a year ago and forget something that happened last night? It all depends on how two distinct parts of the brain process the information, according to studies by neuroscientists from Stanford and Harvard who have been able to take a big step toward solving the mystery by literally peering inside the human brain at the split second it creates a memory. Using new highly sophisticated magnetic resonance imaging scanners on volunteers, the researchers were able to show that neural activity in certain brain regions predicts what experiences will be remembered later. The study at Stanford involved memory for scenic photos while the study at Harvard involved memory for words. Scientists have long suspected that people remember some things better than others partly because of differences in the way the initial experience is encoded into the brain. These studies are the first to show which parts of the brain determine whether a specific, current experience is fated to be remembered or forgotten. The new studies show that when the right prefrontal lobe became active, the experience of seeing an image or a word is significantly more likely to be remembered. The findings may help scientists understand why sufferers of Alzheimer and other forms of senile dementia often have vivid memories of long past events but easily forget things that happened in their daily lives. The individuals in the Stanford study varied greatly on which pictures they remembered well, but the activity levels in each person's brain at the time a picture was viewed predicted if he or she would remember that picture later, said John Gabrieli, associate professor of psychology. "It's interesting to speculate about what could be driving the difference in the activation and the correlating differences in memory," said James Brewer, a graduate student in neuroscience and medicine. "Perhaps one person would see a photograph of Zion National Park and think, 'Hey, I just visited that place on my way to California!' while another would think, 'Outdoor desert scene. . . What's the next scene going to be?' " The first person's memory of the picture would likely be stronger, he said. For more information contact: http://www.stanford.edu/news/report/news/august26/memory826.html
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