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Scientists Create Smart Mouse
A "Doogie" mouse stands on an object used in a learning and memory test. Doogie is a strain of mice that is genetically modified to have improved learning and memory. In the novel object recognition test, the mice were given the chance to become familiar with two objects. Later, when one object was switched for another, Doogie mice quickly recognized the switch and devoted time to exploring the new object instead of the old one. Normal mice spent equal time exploring the new object and the old one.
Joe Tsien, assistant professor of molecular biology
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Double-Keyed Lock. Neurons are equipped with a "coincidence detector" called the NMDA receptor that is triggered only when it receives two signals from independent sources. When it senses such a coincidence, it responds by opening a gate in the cell membrane. In the first picture above, the NMDA receptor is blocked by a magnesium ion. In the second picture, the two signals occur simultaneously: 1) neuron A emits a signal in the form of a glutamate molecule, which binds to the NMDA receptor on neuron B; and 2) the cell membrane of neuron B undergoes a reversal of electrical charge, called depolarization. When both these steps occur, in the final picture, the magnesium ion gets kicked out of the NMDA gate, the channel opens and calcium ions start flowing into the cell. This initiates a chain of events that leads to learning.
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