San Jose ? In a study that could hold promise for children with Down syndrome, Stanford University researchers have found that a long-discredited drug can improve the mental abilities of mice with the genetic disorder, which causes mental retardation in humans.

The mice were better able to navigate mazes and recognize new objects after receiving the drug, and the gains continued for months after treatment stopped. The researchers ultimately hope to test the drug, known as pentylenetetrazole, or PTZ, in people with Down syndrome.

“It’s a very exciting piece of work,” said David Patterson, a Down syndrome researcher at the University of Denver who was not involved in the study.

Both Patterson and the Stanford researchers caution, however, that it is too early to tell if the drug will be successful in people.