A new study has been published. Developmental Cognitive Neuroscience To determine how early life adversity impacts children’s brain development, the researchers found that greater perinatal adversity was associated not only with smaller hippocampal volume in childhood, but also with faster growth of the right hippocampus throughout childhood. Interestingly, this accelerated growth was associated with an increased risk of depressive symptoms later in childhood.
Previous research has shown that children exposed to adversity often experience a range of developmental changes. However, few studies have examined brain development across multiple time points to effectively model the pace of development. Researchers sought to gain a deeper understanding of how perinatal adversity affects the pace of brain development and how that impacts children’s mental health.
“There is a growing body of research suggesting that children exposed to adversity may develop more quickly. For example, they are at higher risk of early puberty and have brains that are physically more typical of older children,” the study authors wrote. Jonas MillerHe is an assistant professor at the University of Connecticut. Biobehavioral Regulation and Neurodevelopment Laboratory.
“However, few studies have measured the brain at multiple time points and effectively modelled the pace and rate of development. It was also unclear whether adversity that occurs very early in life, such as during pregnancy or the first six months of life, has a persistent association with accelerated brain development throughout childhood, and whether the pace of brain development influences children’s future mental health. We were interested in using data from the Growing Up Healthy Outcomes Singapore (GUSTO) study to address these questions.”
The study drew data from the Growing Up Towards Healthy Outcomes in Singapore (GUSTO) study, a comprehensive birth cohort study. Researchers collected neuroimaging data at three time points: ages 4.5, 6, and 7.5. They analyzed these scans to measure the volume of different parts of the brain, with a focus on the hippocampus.
The hippocampus is an important part of the brain located in the temporal lobe. It plays a major role in forming and organizing memories, and is also involved in learning and regulating emotions. This small, curved structure shaped like a seahorse helps consolidate information from short-term to long-term memory.
The sample included 784 children, and the researchers assessed perinatal adversity based on several factors, including birth weight, gestational age, maternal smoking during pregnancy, household income, maternal mental health, and early hospitalization of the child. Each factor contributed to an adversity index, with higher scores indicating greater adversity.
The researchers used magnetic resonance imaging (MRI) to collect high-resolution images of the children’s brains. They then used advanced techniques to segment and measure the volume of specific brain regions, particularly the hippocampus. Finally, when the children were 8.5 years old, they reported their depression symptoms using a standardized questionnaire.
The researchers found that higher levels of perinatal adversity were associated with smaller hippocampal corpuscle volume on both sides of the brain at age 4.5 years. However, these children also showed faster growth of the right hippocampal corpuscle between ages 4.5 and 7.5 years. This accelerated growth was associated with more reported depressive symptoms at age 8.5 years.
“We were surprised to see that prenatal and early postnatal risk factors were associated with children’s mental health 8.5 years later,” Miller told PsyPost.
The findings suggest that early life adversity is biologically embedded in brain development, influencing both the early size and growth rate of the hippocampus. Furthermore, faster growth rate of the right hippocampal corpuscle mediates the relationship between early life adversity and later depressive symptoms, suggesting that altered brain development may underlie the increased risk of depression seen in these children.
“Early life risk factors can accumulate, but so can resources and assets,” Miller explained. “Exposure to multiple adversities during pregnancy and early postpartum, such as parental smoking, hospitalization, and parental mental health issues, can pose risks to a child’s developing brain. This may be especially true when children lack access to early life resources and favorable conditions, such as breastfeeding, a healthy prenatal environment, and parents with good mental health.”
“We find that cumulative adversity early in life, combined with relatively few resources, puts children at increased risk of having a smaller hippocampus at age four – an area that plays an important role in regulating memory, emotions and stress. Despite their smaller hippocampi, these children tend to experience faster growth in this area over the next three years of childhood, but they never seem to catch up with their peers who have been less exposed to adversity.”
“This rapid growth of the hippocampus is in turn associated with an increased risk of children reporting symptoms of depression,” Miller said. “Taken together, our findings suggest that early life conditions may influence the pace of development of some brain regions, which may increase or decrease children’s risk of experiencing depression later in life.”
Although this study provides valuable insights, there are some limitations that should be considered. For example, the cumulative adversity score combines a variety of factors and may not fully capture the complexity of each child’s experience. Future research may benefit from examining specific types of adversity separately.
“These findings are based on a correlational study design,” Miller points out, “so we can’t say that perinatal adversity, the rapid pace of brain development, and future depressive symptoms are causally related to one another.”
“We want to test whether these findings are specific to hippocampal size and growth, or whether they apply to other brain regions, networks and measures. We’re also interested in examining how the pace of brain development affects children’s plasticity and openness to environmental influences. We often think of childhood as a time of increased plasticity. Do accelerated aspects of brain development cause plasticity to decline more quickly?”
“This study would not have been possible without the collaboration of my co-authors and the families participating in the Growing Up Towards Healthy Outcomes Singapore (GUSTO) study,” Miller added.
the study, “Faster hippocampal growth rate mediates the association between perinatal adversity and childhood depression” was written by Jonas G. Miller, Peter D. Gluckman, Marielle V. Fortier, Yap Seng Chong, Michael J. Meaney, Ai Peng Tan, and Ian H. Gotlib.
