The engineered mice were significantly better than normal, though, at learning a water maze, in which they had to find and learn the location of an underwater platform. They were also better at relearning a new position of the platform after it was moved.
When you manipulate a brain, you usually dont improve it, Dr. Sdhof said. The fact that we get an improvement is very good. It shows were changing something specific; were affecting how the brain processes information.
Other tests of coordination, anxiety and motor ability showed normal results, indicating that the changes in brain activity were specific, Dr. S dhof said.
The researchers also studied the patterns of electrical activity in the brain. Normally, some nerve cells halt, or inhibit, other nerve cells from firing, while others excite action in their neighbors. An imbalance in the normal pattern is thought to be involved in autism.
Nerve cells from the genetically engineered mice showed a significantly greater inhibitory action than their normal littermates, even though only about 10 percent of the normal amount of neuroligin-3 was present. This finding was a surprise, as other studies have indicated that a loss of inhibitory action might be involved in autism spectrum disorders, the researchers said.
The results indicate that focusing on inhibitory action might be a way to treat autistic behaviors, said Dr. Sdhof, director of the Gill Center for Research on Brain Cell Communication and the C. Vincent Prothro Center for Research in Basic Neuroscience. He is a Howard Hughes Medical Institute investigator at UT Southwestern.
|Contact: Aline McKenzie|
UT Southwestern Medical Center