Children who are exposed to poverty at a young age often have trouble academically later in life. But according to new research out of the Washington University School of Medicine, poverty also appears to be associated with smaller brain volumes in areas involved in emotion processing and memory.
A team of researchers at the St. Louis-based university, led by Joan Luby, analyzed brain scans of 145 children between the ages of 6 and 12 who had been tracked since preschool, in a study released Monday in the journal JAMA Pediatrics. Aside from the influence environmental factors of poverty may have on a student's behavior and school performance, the researchers found that poverty also appears to alter the physical makeup of a child's brain; those children exposed to poverty at an early age had smaller volumes of white and cortical gray matter, as well as hippocampal and amygdala volumes.
White and gray matter, nerve tissues found in the brain, are associated with sending communications in the brain, as well as sensory perception, memory, emotions and speech, respectively. Meanwhile, the hippocampus is a region of the brain involved in the conversion of short-term memory to long-term memory, and spatial navigation, and the amygdala plays a role in processing memories and emotions. Having smaller volumes of these regions of the brain means those functions may be impaired, the study suggests.
"The finding that exposure to poverty in early childhood materially impacts brain development at school age further underscores the importance of attention to the well-established deleterious effects of poverty on child development," the report says.
Previous research has shown that those damaging effects can rage from poor cognitive outcomes and school performance, to a higher risk for antisocial behaviors and mental disorders.
And the number of children living in poverty continues to grow. A recent Census report found that nearly a quarter of children in the United States, about 16.1 million, lived in poverty in 2012. Before the recession, that number hovered around 17 percent.
But some of the negative effects on the brain, researchers found, can be mediated by the level of support or hostility of the children's caregivers, as well as the level of stressful events in life.
Similar findings from previous research, the study says, suggest supportive parenting plays a role in the development of the hippocampus "independent of income."
The authors argue that caregiving should be a target when developing preventive interventions because children with more supportive caregiving could also avoid exposure to more stressful life events, which can have a negative effect on hippocampal development.
In an editorial on the study, also published in the journal Monday, Charles Nelson of the Boston Children's Hospital and Harvard Medical School, writes that a limitation of the study is the fact that children with depression or who were at high risk for developing depression were overrepresented in the sample. That population could skew the overall picture, Nelson writes, because it's possible that childhood depression could have influenced the results and could increase family stress.
Still, Nelson argues that the findings support the idea that intervention strategies targeting high-risk families should start as early as birth.
"If we wish to protect our children's brains, we must work hard to protect their young minds," Nelson writes. "Exposure to early life adversity should be considered no less toxic than exposure to lead, alcohol, or cocaine, and, as such, it merits similar attention from public health authorities."