Brain Discovery

By Jerilyn Watson

This is Bill White with the VOA Special English Science Report.

Researchers in Britain have reported that a small area in the brain may be responsible for solving difficult problems. The scientists were led by John Duncan of the Medical Research Council in Cambridge. They say they may have found the area of the brain responsible for general intelligence. The area is called the lateral prefrontal cortex. It is found on both sides of the brain above the outer edge of the eyebrows. The research was reported in the journal, Science.

Doctor Duncan and his team tested sixty people. They were between the ages of twenty-nine and fifty-one. The scientists studied the peoples' brains as they answered questions similar to those on an intelligence test. For example, the people were required to look at four pictures. They had to decide which picture was not similar to the others. They also had to decide which of four groups of letters was different from the other three.

The researchers studied brain activity as these people worked on the problems. The team did this by using a technology called positron emission tomography, or PET scans. PET scans measure which brain cells use the most blood at any moment by lighting up those areas. This technology tells which areas of the brain are working hardest.

The goal of the research was to discover if large areas of the brain would light up or if only a limited area would light up during the tests. The research showed that only the lateral prefrontal cortex lighted up as the people solved the problems. The research also showed that the same area of the brain was used in two different kinds of thinking.

Some earlier studies have shown that this area of the brain is important for keeping many things in mind at the same time. The lateral prefrontal cortex also has been shown to block information that is not important at the time.

However, the research did not show if there are differences in the lateral prefrontal cortex in people who do well on intelligence tests and those who do not. Also, scientists do not know if an intelligent person is born with a highly effective prefrontal cortex or if the area develops with learning and experience.

This VOA Special English Science Report was written by Jerilyn Watson. This is Bill White.