for National Geographic News
By modifying a single gene, scientists have made Hobbie-J the smartest rat in the world, a new study says.
A similar gene tweak might boost human brainpower too, but scientists warn that there is such a thing as being too smart for your own good.
For years scientifically smartened rats have skittered through movies and books such as Flowers for Algernon and The Secret of NIMH. But Hobbie-J is anything but fiction.
The lab rat can remember objects three times longer than her smartest kin, the study says. Thanks largely to this memory boost, she's also much better at solving complex tasks, such as traveling through mazes using only partial clues to find rewards—a key method for measuring rat intelligence.
When Hobbie-J was still an embryo, a team led by Joe Z. Tsien at the Medical College of Georgia injected her with genetic material that caused the overexpression of the gene NR2B, which helps control the rate at which brain cells communicate.
The change allowed Hobbie's brain cells to communicate for a whisker of a second longer than those of normal rats. This, the researchers believe, is why she's much smarter than the average rat.
Years earlier Tsien and colleagues had given a similar brain boost to a mouse named Doogie, after TV whiz kid Doogie Howser, M.D.
Like the rats of NIMH—"NIMH" being shorthand for the U.S. National Institute of Mental Health—Hobbie-J and Doogie were given intelligence in hopes that the experiments would lead to cures for human brain disorders.
(Related: animal-intelligence pictures.)
"NR2B functioned as a switch to improve learning and memory skills in Doogie, and it is showing the same results in Hobbie-J," Tsien said via email.
"This suggests that using drugs to target this gene may help to resolve disorders like dementia and Alzheimer's disease," he added.
Neuroscientist Guosong Liu, who worked on the Doogie project, said: "The research is all very exciting, because it raises the possibility for us to potentially enhance memory in humans, and that is exactly where my lab is going."
But there are two major challenges ahead, said Liu, of Tsinghua University in Beijing and the University of Texas, who was not involved in the new study.
First, because genetically modifying human embryos is not considered ethical, doctors would have to find a way to amplify NR2B expression using drugs instead, he said.
Second, mega-memory could be a major burden, even a nightmare, Liu said.
"There is a reason we forget," he said. "We are supposed to leave our bad experiences behind, so they do not haunt us."
For this reason, if a drug does become available for human use, Liu said he would only advocate its use in people suffering from significant mental problems such as Alzheimer's disease.
"The danger of extending memory in healthy people could be considerable" Liu said.
Findings published October 19 in the online journal PLoS ONE.
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