Mothers’ support linked to robust growth of brain area involved in learning, memory, stress response.
Children whose mothers were nurturing during the preschool years, as opposed to later in childhood, have more robust growth in brain structures associated with learning, memory and stress response than children with less supportive moms, according to research at Washington University School of Medicine in St. Louis.
“This study suggests there’s a sensitive period when the brain responds more to maternal support,” said first author Joan L. Luby, MD, a Washington University child psychiatrist at St. Louis Children’s Hospital.
The study is published online April 25 in the Proceedings of the National Academy of Sciences Early Edition.
The researchers studied a series of brain scans of children from preschool through early adolescence, finding a sharper rise in the volume of the hippocampus in the kids whose mothers supported and nurtured them during the preschool years. That region of the brain is critical to learning, memory and regulating emotions. In contrast, the hippocampus appeared smaller in adolescents whose mothers were less supportive during the preschool period, even if their mothers became more supportive in elementary or middle school.
The new research builds on previous findings by the same investigators that showed a link between maternal nurturing and a larger hippocampus observed in brain scans conducted at the time the children reached school age. In the new study, the researchers were able to observe steady growth in the hippocampus of children with supportive mothers across multiple brain scans taken at different time periods, with 127 children receiving three MRI scans each from the time they first started school through early adolescence.
“The parent-child relationship during the preschool period is vital, even more important than when the child gets older,” Luby said. “We think that’s due to greater plasticity in the brain when kids are younger, meaning that the brain is affected more by experiences very early in life. That suggests it’s vital that kids receive support and nurturing during those early years.”
The researchers also found that the growth trajectory in the hippocampus was associated with healthier emotional functioning when the children entered their teen years. When parental nurturing didn’t begin until later in childhood, such support didn’t provide the same benefits in brain growth, the researchers noted.
“This finding highlights the critical importance of caregiving in sculpting aspects of brain development that are important to how children function as they mature,” said co-author Deanna M. Barch, PhD, a Washington University Psychologist and chair of the Department of Psychological & Brain Sciences.
The researchers measured nurturing in mothers by closely observing and scoring videotaped interactions between mothers and their children. The investigators observed mothers and children under moderately stressful conditions, explained Luby, the Samuel and Mae S. Ludwig Professor of Child Psychiatry and director of Washington University’s Early Emotional Development Program.
“The mother is asked to complete a task while we give the child an attractive gift to open, but we don’t allow it to be opened right away,” she said. “It’s a stressful condition like those that happen multiple times each day in any given family, like when you’re cooking dinner and a child wants attention. The child needs something, but you have something else to do, so it challenges your parenting skills.”
Parents who are able to maintain their composure and complete assigned tasks while still offering emotional support to their children are rated as more nurturing and supportive. Parents who dismiss their children, or behave in punitive ways during the test, receive lower marks for support.
Small changes in support indicated big differences in outcomes, Luby said. In examining the brain scans, the researchers found that children whose mothers were more supportive than average had increases in growth of the hippocampus that were more than two times greater than in those whose mothers were slightly below average on the nurturing scale.
Luby believes the findings suggest it may be possible to help children do better in school, cope better in life and develop emotionally by helping parents learn to provide more support and nurturing early in the lives of their children.
“Early maternal support affects the child’s brain development,” she said. “We also know that providing support to parents can have a positive impact on other behavioral and adaptive outcomes in children. So we have a very logical reason to encourage policies that help parents become more supportive.”
Funding: This work was supported by the National Institute of Mental Health and the National Institutes of Health Blueprint of the National Institutes of Health (NIH), grant number R01 MH090786.
Source: Jim Dryden – Washington University School of Medicine
Image Source: The image is credited to Washington University School of Medicine.
Original Research: Full open access research for “Preschool is a sensitive period for the influence of maternal support on the trajectory of hippocampal development” by Joan L. Luby, Andy Belden, Michael P. Harms, Rebecca Tillman, and Deanna M. Barch in PNAS. Published online April 25 2016 doi:10.1073/pnas.1601443113
Abstract
Abnormalities in Diffusional Kurtosis Metrics Related to Head Impact Exposure in a Season of High School Varsity Football
Building on well-established animal data demonstrating the effects of early maternal support on hippocampal development and adaptive coping, a few longitudinal studies suggest that early caregiver support also impacts human hippocampal development. How caregiving contributes to human hippocampal developmental trajectories, whether there are sensitive periods for these effects, as well as whether related variation in hippocampal development predicts later childhood emotion functioning are of major public health importance. The current study investigated these questions in a longitudinal study of preschoolers assessed annually for behavioral and emotional development, including observed caregiver support. One hundred and twenty-seven children participated in three waves of magnetic resonance brain imaging through school age and early adolescence. Multilevel modeling of the effects of preschool and school-age maternal support on hippocampal volumes across the three waves was conducted. Hippocampal volume increased faster for those with higher levels of preschool maternal support. Subjects with support 1 SD above the mean had a 2.06 times greater increase in total hippocampus volume across the three scans than those with 1 SD below the mean (2.70% vs. 1.31%). No effect of school-age support was found. Individual slopes of hippocampus volume were significantly associated with emotion regulation at scan 3. The findings demonstrate a significant effect of early childhood maternal support on hippocampal volume growth across school age and early adolescence and suggest an early childhood sensitive period for these effects. They also show that this growth trajectory is associated with later emotion functioning.
“Preschool is a sensitive period for the influence of maternal support on the trajectory of hippocampal development” by Joan L. Luby, Andy Belden, Michael P. Harms, Rebecca Tillman, and Deanna M. Barch in PNAS. Published online April 25 2016 doi:10.1073/pnas.1601443113
