- Scientists have engineered mice that, in mazes at least,
can run rings around ordinary rodents. The research shows the importance
of nerve growth in boosting brain performance. Professor Aryeh Routtenberg,
and colleagues from Northwestern University, US, used mice that had been
modified so that their brains expressed enhanced levels of a protein that
stimulates nerve fibre growth.
- More nerve fibres in the brain meant that the mice were
quicker at learning tasks such as hunting for food in a maze. The mice
also remembered how to do the tasks much longer than the "wild type"
- Second gene
- The gene for the protein is the second single gene that
has been shown to significantly improve learning and memory. In September
1999, another US team showed that a gene called NR2B helped keep mouse
brains "young", with lots of interconnections between the neurons.
- The extra gene in the mice in this latest study produces
a growth-associated protein called as GAP-43. It is found early in the
development of all animals, when neurons are deciding where and how to
grow. It acts on the ends of nerves, not only stimulating them to grow
but also providing more resources for the brain's memory functions.
- Mice that overproduced the GAP-43 protein performed better
than the mice with normal GAP-43 levels in experiments designed to test
the ability to remember the location of food in a maze.
- In addition, when the interval between the tasks was
lengthened the superiority of the altered mice was more pronounced.
- Ethical questions
- Professor Routtenberg said he would oppose moves to create
a designer drug for people who want to be smarter, or who want their children
to have an advantage in school.
- "You get into ethical questions," he said.
- "But I think that we are moving ever closer to finding
an agent that will facilitate when we are learning." Legitimate uses,
in his opinion, would be in treating people with Alzheimer's, some with
mental retardation and perhaps people suffering from age-related memory
loss. He said there was evidence that GAP-43 was produced in lower amounts
as people aged.
- The research is reported in the Proceedings of the National
Academy of Science.
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