Washington ? Aging brains may be sharpened and, in effect, made young again briefly by increasing the levels of a neurochemical called GABA, a study suggests.

Researchers at the University of Utah found that GABA appears to help extremely old Rhesus monkeys focus their vision and thinking processes by silencing the interfering static from other neurons.

GABA screens out the stray brain signals that may make thinking and seeing difficult in older brains, said Audie G. Leventhal, a professor at the University of Utah School of Medicine.

“It eliminates the garbage signals,” said Leventhal, first author of the study appearing today in the journal Science.

Leventhal said in old primates, both human and monkey, there was a decline in the levels of GABA, a chemical that inhibits neuron signals in the brain.

Without enough of that control, he said, the brain is distracted and overwhelmed by stray signals, in the same way the ear is overwhelmed when trying to hear a whisper at a rock concert.

“There, you wouldn’t really hear anything,” he said. “But if there is screaming in an empty room, then it is very easy to hear. That is sort of what GABA does.”

Without sufficient levels of GABA to drown out the background signals, Leventhal said, “then all of your higher brain functions go bad.”