Word: mice
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Dates: during 1990-1999
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...altered mice grow up looking and acting just like ordinary mice, with no evidence of seizures or convulsions, according to Tsien. That's critical. The NMDA receptor shows up throughout the brain, and though calcium is crucial to learning and memory, too much of it can lead to cell death. That's what happens during a stroke: when brain cells are deprived of oxygen, they release huge amounts of glutamate, which overstimulates nearby NMDA receptors and kills their host cells. Nature may have designed NR2B-based receptors to taper off in adult brains for a reason. Some scientists fear that...
...will be a while before such dangers arise, though, and--as cancer researchers have discovered all too often--it isn't even certain that what works in mice will work in people. Tsien and his colleagues believe it's not unreasonable to think it will. "The NMDA receptor in humans is nearly identical to the receptor in mice, rats, cats and other animals," he says. "We believe it's highly likely that it plays a similar role in humans...
...paper was sure to generate controversy. "We really don't mean to suggest," he explains, "that human intelligence is the same as animal intelligence. But I would argue that problem solving is clearly part of intelligence, and learning and memory are crucial to problem solving. And these mice are better learners, with better memories, than other mice...
...like a Christmas tree," says Thomas Murray, Hastings' director. "If you make a change in one area, it may cause very subtle changes in some other area. Will there be an imbalance that the scientists are not looking for, not testing for, and might not even show up in mice...
...scientists bred strains of mice with extra copies of a gene coded for a protein that can facilitate communication between neurons. Since one popular theory of memory relates this primary mental capacity to an organism's ability to make associations--say, between a bee's buzz and the pain of its bite--this enhanced communication might promote the recording of associations within the brain, thus creating memories...