4 December 2008

Striking differences between brains of rich and poor

by Kate Melville

A new study in the Journal of Cognitive Neuroscience by researchers from the University of California, Berkeley, has shown for the first time that the brains of low-income children function differently from the brains of high-income kids. UC Berkeley's Robert Knight says that normal 9 and 10-year-olds differing only in socioeconomic status have detectable differences in the response of their prefrontal cortex, the part of the brain that is critical for problem solving and creativity.

Previous studies have shown a possible link between frontal lobe function and behavioral differences in children from low and high socioeconomic levels, but this new study is the first to directly measure brain activity where there is no issue of task complexity.

Knight's team measured the kids' brain function using an electroencephalograph (EEG) - basically, a cap fitted with electrodes to measure electrical activity in the brain. They found that kids from lower socioeconomic levels showed brain physiology patterns similar to someone who had damage in the frontal lobe as an adult. "We found that kids are more likely to have a low response if they have low socioeconomic status, though not everyone who is poor has low frontal lobe response," remarked Knight.

The study notes that the children had no neural damage, yet the prefrontal cortex was not functioning as efficiently as it should be. The researchers suspect that stressful environments and cognitive impoverishment are to blame, since in animals, stress and environmental deprivation have been shown to affect the prefrontal cortex. UC Berkeley's Marian Diamond, professor emeritus of integrative biology, showed nearly 20 years ago in rats that enrichment thickens the cerebral cortex as it improves test performance.

Co-author W. Thomas Boyce, UC Berkeley professor emeritus of public health, is not surprised by the results. "We know kids growing up in resource-poor environments have more trouble with the kinds of behavioral control that the prefrontal cortex is involved in regulating. But the fact that we see functional differences in prefrontal cortex response in lower socioeconomic status kids is definitive."

"This is a wake-up call," Knight added. "It's not just that these kids are poor and more likely to have health problems, but they might actually not be getting full brain development from the stressful and relatively impoverished environment associated with low socioeconomic status: fewer books, less reading, fewer games, fewer visits to museums."

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Source: University of California - Berkeley