Racial discrimination and prejudice are painful realities and are increasingly recognized as harmful to the health of adults and children.
These stressful experiences also appear to be transmitted from mother to child during pregnancy, altering the strength of infants’ brain circuits, according to a new study by researchers at Columbia, Yale and Children’s Hospital Los Angeles.
The study found similar brain changes in infants whose mothers experienced stress from adapting to a new culture during pregnancy.
“A key hypothesis would be that the connectivity changes we see could reduce one’s ability to regulate one’s emotions and increase one’s risk for mental health disorders,” says lead study author Marisa Spann, PhD, Herbert Irving Associate Professor in Medical Psychology in the Department of Psychiatry at Columbia University Vagelos College of Physicians and Surgeons.
“Whether the connectivity differences we found lead to long-term mental health outcomes in children remains to be seen. Our team and others in the field still have an opportunity to test this.”
Previous research by Spann and colleagues has documented the impact of various forms of prenatal distress — depression, stress and anxiety — on the infant’s brain. “We work with vulnerable and underrepresented populations, and experiencing stigma and discrimination is very common,” says Spann. “This naturally led to discussions about the impact of other stressors, such as discrimination and acculturation, on the infant brain.”
In the new study, researchers analyzed data collected from 165 young, mostly Hispanic women who had participated in a previous study on teenage pregnancy, stress and diet by co-authors Catherine Monk, PhD, and Bradley Peterson, MD . Data included self-reported measures of discrimination and acculturation, along with measures of general stress, childhood trauma, depression, and socioeconomic status.
An analysis of the data showed that stress from discrimination and acculturation was separate and distinct from other types of stress and may have unique effects on the brain.
To look for these unique effects, the researchers compared mothers’ discrimination and acculturation stress with the strength of their infants’ brain circuits, as measured by MRI scans. This analysis of 38 mother-infant pairs showed that infants of mothers who experienced discrimination generally had weaker connections between their amygdala and prefrontal cortex, and infants of mothers who experienced focal anxiety had stronger connections between the amygdala and another brain region that it is called fusiform.
The amygdala is a brain region associated with emotional processing that is altered in many mood disorders. It can also be involved in ethnic and racial processing, such as face differentiation.
“The amygdala is very sensitive to other types of prenatal stress,” says Spann, “and our new findings suggest that experience of discrimination and acculturation also affects amygdala circuitry, possibly across generations.”
The message, Spann says, is that “how we behave and interact with people matters, especially during pregnancy — a critical time when we can see the far-reaching effects on children.”
Spann adds that more research is needed to explore the biological mechanisms that transmit the experiences of adversity from parents to offspring, as well as the long-term impact of these findings. She is currently leading a study — funded by the Community Participatory Research Program of Columbia’s Irving Institute for Clinical and Translational Research and in collaboration with the Northern Manhattan Perinatal Partnership — to examine the relationship between maternal experiences of discrimination and cultural stress in development of their infant racial processing.
The new research was supported by the National Institute of Mental Health (grants K24MH127381, R01MH126133, and R01MH117983). the National Center for Advancing Translational Sciences (TL1TR001875); the National Institute of Health and Lung and Blood Diseases (R25HL096260); the BEST-DP: Biostatistics & Epidemiology Diversity Summer Training Program. Eunice Kennedy Shriver National Institute for Child Health and Human Development (K23HD092589); and an Irving Scholar Award from the Irving Institute for Clinical and Translational Research at Columbia University.
Catherine Monk and Bradley Peterson provided data from a previous study, which was supported by a grant from the National Institute of Mental Health (R01MH093677).
Catherine Monk, PhD, is the Diana Vagelos Professor of Women’s Mental Health in the Department of Obstetrics & Gynecology at Columbia University Vagelos College of Physicians and Surgeons and directs the department’s Center on the Transition to Parenthood. She is also a professor of Medical Psychology in the Department of Psychiatry.
The authors declare no competing interests.