Socioeconomic conditions may have a greater impact on neurological development than previously thought.
By: James Swift
A slate of recent reports have emerged indicating that childhood stressors stemming from living in impoverished conditions may have long term effects on mental functioning.
One study, published in the Proceedings of the National Academy of Sciences, examined 49 subjects, all of whom were participants in a longitudinal study gauging the effects of childhood poverty.
Both physical stressors, like living in substandard housing, and social stressors, such as experiencing or witnessing domestic violence, were evaluated as part of the study. According to researchers, subjects who had experienced such stressors at age 9 were more likely to experience greater amygdala activity, alongside lower prefrontal cortex activity, as 24-year-olds.
The amygdala is the part of the brain most closely associated with processing negative emotions, such as fear, while the prefrontal cortex is most closely associated with regulating emotions. Dysfunction in both parts of the brain, researchers said, have been associated with numerous mental disorders, including anxiety and depression.
Using magnetic resonance imaging (MRI), researchers assessed subjects’ neural activity while being shown images designed to evoke negative reactions.
“If you tended to be growing up poor when you were 9-years-old, now as a young adult at the age of 24, you tended to engage less of specific areas of your prefrontal cortex, that are supposed to be engaged while you’re trying to regulate negative affect,” said Dr. K. Luan Phan, senior study author and psychiatry professor at the University of Illinois-Chicago’s College of Medicine.
“The brain is developing rapidly, especially in the prefrontal cortex, throughout adolescence,” Phan added. “Through chronic stress as the child grows up through adolescence, it might have a long-lasting effect on brain functioning.”
In another study, published in JAMA Pediatrics, researchers determined that young people who had experienced poverty-related stressors as children tended to have lower hippocampus and amygdala volumes than children who did not.
Researchers, using longitudinal data from the Washington University School of Medicine, examined MRI images of subject’s brains and collected information on the children’s home lives and behavior. Ultimately, the authors of the study concluded that childhood poverty was associated with “smaller white and cortical grey matter” in the subjects’ brains, an indication that stressors experienced in early childhood may impact mental development during early adolescence.
“The most important finding is that evidence that parental nurturance can protect the brain against the negative effects of poverty during childhood,” said Dr. Joan Luby, lead report author and director of Washington University’s Early Emotional Development Program. “This has huge public health implications as it suggests some of the negative effects of poverty on emotions and behavior might be preventable with a targeted intervention.”
A key takeaway from the study, she said, is the importance of building strong caregiver bonds with young people who may be living in impoverished conditions.
“The focus should be on developing positive and supportive caregiver relationships with children, no matter what age or what adversity they face,” she said. “This is essential to healthy child development.”
Some research indicates that environmental poverty may also lead to sensory impoverishment -- an underexposure to cognitive stimulus coupled with an overexposure of environmental toxins, such as noise pollution.
A third report, conducted by researchers at Northwestern University and published late last month in the Journal of Neuroscience, draws connections between lower maternal education and a child’s mental ability to process auditory information.
Children were broken into two groups, with the education of their mothers used as a socioeconomic status (SES) correlate. Not only did the children from lower maternal educational backgrounds have lower cognitive and literacy levels, researchers even stated the neural activities in their brains were “noisier” compared to other children.
“The neural response to speech was more erratic over repeated stimulation, with lower fidelity to the input signal,” the report reads. “These weaker, more variable and noisier responses are suggestive of an inefficient auditory system.”
Nina Kraus, report author and professor of Neurobiology & Physiology at the Northwestern School of Communication, said the research findings not only underscore the importance of education for today’s children, but potentially future generations as well. More research on the impact of enrichment measures on other poverty metrics, she said, could lead to a greater understanding of how social conditions influence the developing brain.
“Objective, biological data is hugely important to our understanding of social issues such as the achievement gap,” she said. “The better we understand the biological impact of SES the better positioned we’ll be to address the impact constructively.”
Uncommon Journalism, 2013.