The experiments began by injecting mouse embryos with an extra copy of the NR2B gene, which controls the brain's ability to link one event to another and remember the link. This "double whammy" of the gene will quicken the way the mice learn and remember by speeding up the reactions between neurons, or brain cells. After insertion was complete, Joe's team observed the new transgenic mice, now named Doogie, along with other wild-type mice. One observation was how transgenic mice compared to wild-type mice in learning and memory experiments. The last experiment performed was a test for spatial learning. In all three experiments, the transgenic mice showed better and faster learning and memory abilities than the wild-type mice.

NMDA receptor. Research indicates that when the NMDA receptor channel is open, triggered by a stimulus from two neurons, "it begins a biochemical cascade that results in memory retention and learning (Bassand 1999)." In simpler terms, the extra copy of the NR2B gene controls the brain's ability to link one event to another and remember the link. "This "double whammy" of the gene quickened the way the mice learn and remember by speeding up the reactions between neurons, or brain cells (Guynup 2000)." Tsien accomplished this task by taking a copy of the gene that directs the production of NR2B and linking it to a special piece of DNA. This DNA contained a special on switch to increase the gene's ability to make the protein in the adult brain. This was then injected into fertilized mouse eggs where it was incorporated into the chromosomes of the mice. Tsien then set out to prove the theory that overexpression of NR2B in the brains of mice, leads to enhanced activation of NMDA receptors, which in turn leads to superior ability in learning and memory.

The last experiment performed was a test for spatial learning which also requires the activation of NMDA receptors in the hippocampus. The particular behavioral test is called the "Morris water maze." This more complicated task "involves many cognitive factors, including analytical skills, learning and memory, and the ability to form strategies (Tsien 2000)." For this test the mice would use visual cues on a laboratory wall to find the location of a submerged platform hidden in a pool of milky water. Since mice don't like to get wet they were inclined to find the platform by simply swimming around until they had discovered it. This platform would then place them slightly out of the milky waters. Taking the test a step further, they platform was removed from its original spot. Using the cues on the laboratory wall the transgenic mice were more likely to swim to it's original location, indicating they had remembered were it should be. This again confirms better learning and memory in transgenic mice.

Joe Tsien and his group reported in the September 2, 1999 issue of Nature that they had successfully "boosted the intelligence of mice" (Ya-Ping 1999). This experiment "marks the first time that genetic manipulation has successfully led to NMDA (N-methyl-D-asparate) enhancement in mammals. This report explains how Joe Tsien and his colleges went about proving the theory that overexpression of NR2B in the brains of mice, leads to enhanced activation of NMDA receptors, which in turn leads to superior ability in learning and memory.

The NMDA receptors consist of NR1 subunits and various NR2 subunits. The NR1 subunit is needed for channel function and the NR2 subunit regulates channel gating and Mg2+ depen

Some common words found in the essay are:
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