VOA常速英语:Electric Brain Stimulation Helps Numeric Learning

Researchers in Britain say electric brain stimulation might one day be used to restore abilities lost through illness or maybe just help a prospective engineering student improve her math skills. 

An estimated 20 percent of the population has trouble working with numbers. That's as many as one person in five with some sort of numerical disability. The British researchers are exploring ways to stimulate the brain to improve the ability to understand and work with numbers.

If you look at two numbers - say, seven and two - most of us  know at a glance, almost instinctively, which one is bigger. Scientists at the University of Oxford led by Roi Cohen Kadosh have been trying to understand what goes on in the brain when we work with numbers.

In the latest in a series of research papers, Cohen Kadosh describes how electrical brain stimulation can affect the process.

"We wanted to see if, when we give [numerical information for people to learn] - so, to learn a new numerical system - if stimulating their brain will improve their ability to learn and to act on this learned material," he said in a telephone interview.

To try to answer the question, the scientists recruited 15 people and divided them into groups. Some of the subjects got a small electric current directed at the part of the brain that handles mathematical tasks. Not enough for a shock, just a brief tingle. Others got a fake, placebo treatment.

Then, they were given tests to evaluate their skill with numbers, using a set of made-up symbols instead of actual numbers.

Some people who got the electric stimulation showed significantly better performance in the tests.

Others were significantly worse, depending on how the current was applied.

Cohen Kadosh says the electric current apparently affects brain chemistry in a way that makes the brain cells more adaptable, a feature called plasticity. "And this is what we want eventually to do in these cases, where people have some problems [learning] correctly," he said.

This kind of stimulation may affect more than just numerical skill. Cohen Kadosh says other researchers are studying how it might be used to alleviate pain, or help restore speech after a stroke, to name just two.

This is still just a laboratory finding but the effect of six, 20-minute stimulation sessions is long-lasting and persists for at least six months. The results of electrical stimulation are promising enough that Cohen Kadosh and his team are patenting the process.