A child’s brain is designed to absorb information at a fast pace: During the first few years of life, they create 700 to 1,000 new neural connections every second, making their early years integral to how their brain functions for the rest of their childhood and adolescent development. Knowing this, a team of researchers from Washington University School of Medicine studied parental impact at each stage of development, and discovered the earlier parents invest in their child’s brain structure growth, the better.

"There's a sensitive period when the brain responds more to maternal support," said the study’s co-author Dr. Joan L. Luby, MD, St. Louis Children's Hospital, in a statement. "The parent-child relationship during the preschool period is vital, even more important than when the child gets older. 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. It's vital that kids receive support and nurturing during those early years."

For the study, published in Proceedings of the National Academy of Sciences, researchers recruited 127 children who underwent three magnetic resonance imaging (MRI) brain scans from the time they started school up until they entered into their teenage years in middle school. During the same timeframe, researchers observed and recorded how their parents interacted with their children while they were both under moderately stressful conditions.

"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," said the study’s co-author Deanna M. Barch, a Washington University Psychologist, in a press release. "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."

They compared the children’s brain scans to how their parents interacted with them and found those whose mothers supported and nurtured them early on, during their most formative preschool years, had a sharp rise in cognitive growth, specifically in the hippocampal region. The hippocampus is responsible for learning, memory, and emotional processing. Meanwhile, children whose parents invested more time into the child’s elementary or middle school stages of development instead of their preschool years had smaller hippocampal regions.

Researchers believe if children are nurtured earlier in their lives, they will end up with healthier emotional processing, perform better in school, and cope with exceptional skill by the time they enter their teenage years. By emphasizing the importance of providing nurture and support early on, parents could focus their attention during the right stages of childhood.

"This finding highlights the critical importance of caregiving in sculpting aspects of brain development that are important to how children function as they mature," Barch said. "Early maternal support affects the child's brain development. 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."

Source: Luby JL, Belden A, Harms MP, Tillman R, and Barch DM. Preschool is a sensitive period for the influence of maternal support on the trajectory of hippocampal development. Proceedings of the National Academy of Sciences . 2016.