posted on Jan, 25 2010 @ 11:45 AM
Kishiyama, Knight, Boyce and their colleagues selected 26 children ages 9 and 10 from a group of children in the WINKS study. Half were from families
with low incomes and half from families with high incomes. For each child, the researchers measured brain activity while he or she was engaged in a
simple task: watching a sequence of triangles projected on a screen. The subjects were instructed to click a button when a slightly skewed triangle
flashed on the screen.
The researchers were interested in the brain's very early response - within as little as 200 milliseconds, or a fifth of a second - after a novel
picture was flashed on the screen, such as a photo of a puppy or of Mickey and Minnie Mouse.
"An EEG allows us to measure very fast brain responses with millisecond accuracy," Kishiyama said.
The researchers discovered a dramatic difference in the response of the prefrontal cortex not only when an unexpected image flashed on the screen, but
also when children were merely watching the upright triangles waiting for a skewed triangle to appear. Those from low socioeconomic environments
showed a lower response to the unexpected novel stimuli in the prefrontal cortex that was similar, Kishiyama said, to the response of people who have
had a portion of their frontal lobe destroyed by a stroke.
"When paying attention to the triangles, the prefrontal cortex helps you process the visual stimuli better. And the prefrontal cortex is even more
involved in detecting novelty, like the unexpected photographs," he said. But in both cases, "the low socioeconomic kids were not detecting or
processing the visual stimuli as well. They were not getting that extra boost from the prefrontal cortex."
"These kids have no neural damage, no prenatal exposure to drugs and alcohol, no neurological damage," Kishiyama said. "Yet, the prefrontal cortex
is not functioning as efficiently as it should be. This difference may manifest itself in problem solving and school performance."
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 of integrative biology, showed nearly 20 years ago in rats
that enrichment thickens the cerebral cortex as it improves test performance. And as Boyce noted, previous studies have shown that children from poor
families hear 30 million fewer words by the time they are four than do kids from middle-class families.
"In work that we and others have done, it really looks like something as simple and easily done as talking to your kids" can boost prefrontal cortex
performance, Boyce said.
"We are certainly not blaming lower socioeconomic families for not talking to their kids - there are probably a zillion reasons why that happens,"
he said. "But changing developmental outcomes might involve something as accessible as helping parents to understand that it is important that kids
sit down to dinner with their parents, and that over the course of that dinner it would be good for there to be a conversation and people saying
things to each other."
"The study is suggestive and a little bit frightening that environmental conditions have such a strong impact on brain development," said Silvia
Bunge, UC Berkeley assistant professor of psychology who is leading the intervention studies on prefrontal cortex development in teenagers by using
functional magnetic resonance imaging (fMRI).
Boyce's UBC colleague, Adele Diamond, showed last year that 5- and 6-year-olds with impaired executive functioning, that is, poor problem solving and
reasoning abilities, can improve their academic performance with the help of special activities, including dramatic play.
Bunge hopes that, with fMRI, she can show improvements in academic performance as a result of these games, actually boosting the activity of the