Wired for math.

The same neural circuits that adults use to perform complex calculations are already at work in preschoolers doing basic math, a new study finds. This result suggests that the brain is set up to process numbers early in life.

How the brain graduates from simple counting to more-advanced mathematics, which uses symbols and requires reasoning, isn't clear, says Jessica Cantlon of Duke University in Durham, N.C. One important question has been whether the same region of the brain, called the intraparietal sulcus (IPS), that's active when adults do sophisticated sums also controls basic math skills.

"Intuitively, it would seem that those [skills] are really separate," Cantlon says.

To test IPS' role, she and her colleagues used magnetic resonance imaging to measure changes in blood flow in the brains of 4-year-old children and young adults performing numerical tasks. The subjects watched a stream of computer images of different numbers of squares, circles, and triangles. During repeated shape changes for the objects, IPS activity declined in both adults and children. But the IPS kicked into gear in both groups when the number of objects was changed, the researchers report in the May PLoS Biology.

"The take-home message is that by at least 4 years [of age], your brain is learning how to deal with quantitative information," Cantlon says. "The same brain circuits appear to be important for doing mathematical tasks your whole life."--C.G.