The researchers genetically engineered mice to lack an enzyme called Cdk5 in their brains by using the technique called 'conditional knockout', which made the animal more adept at learning and quicker at figuring out the changes in their environment, as compared to other normal rats.
"It's pretty rare that you make mice 'smarter,' so there are a lot of cognitive implications," Nature magazine quoted senior study author Dr. James Bibb, Assistant Professor of Psychiatry, as saying.
"Everything is more meaningful to these mice. The increase in sensitivity to their surroundings seems to have made them smarter," he added.
The researcher said that the genetically engineered mice were found to be more adept at learning to navigate a water maze, and remembering that being in a certain box involved a mild shock. He further said that when the water maze was rearranged, the engineered mice were much faster to realize that things were different, and worked out the new route.
Normally, Cdk5 works with another enzyme to break up a molecule called NR2B, which has previously been implicated in the early stages of learning.
The new research showed that when Cdk5 is removed from the brain, the levels of NR2B significantly increase, and the mice are primed to learn, said Dr. Bibb.
"Being able to turn a gene off throughout a brain is a really advanced thing to do. It's been shown that it can be done, but we put the system together and actually applied it," he said.
Since Cdk5 is heavily implicated in Alzheimer's disease and addiction to drugs of abuse, Dr. Bibb believes that the understanding of how the enzyme affects the brain and behavior may aid in the development of new treatments for these conditions and post-traumatic stress disorder.
"We made the animals 'smarter,' but in doing so and applying this technology, we also found biochemical targets that hold promise for future treatments of a variety of cognitive disorders," Dr. Bibb said.
He, however, admitted that the long-term effects of deleting the Cdk5 enzyme are yet to be determined. He also said that studies were going on to develop drugs that would help create the same effects without genetic manipulation.
The study also showed nerve-cell firings in the hippocampus, an area of the brain associated with learning. Hippocampus slices from the knock-out mice responded much more strongly to an electrical stimulation, supporting the finding that the mice were more prepared to learn.