Brain scans of 1,099 children and teenagers from nine major cities in the United States showed that the brain surface area is smaler in children who come from poor families.

The brain surface area is significant because this is where the brain cells responsible for intelligence are located. The brain has deep furrows and wrinkles because it has to fit into a small skull. If the wrinkles could expand, the brain would be much larger than it looks.

The study showed that socioeconomic conditions have a very big impact in the early period of brain development. Especially large differences were observed in the regions responsible for speech and reading, memory, decision-making ability and understanding of spatial relations.

Scientists explained that larger area of the brain of children from wealthier parents comes from balanced diet that provides the brain with important nutrients, but it is also the fact that wealthy parents encourage their children's mental activity to a greater extent than poor parents.

Scientists compared the income and education of parents before using a scanner to measure the surface of the brain in children and teenagers. Then they compared the results of cognitive tests, taking into account other factors that may influence the development of the brain -- for example, genes.

It has been shown that socioeconomic conditions are very important for the manner of functioning of the brain. But even small improvements, such as an increase in family income or improved nutrition and education, could affect brain development.