Brain scans of premature and full-term babies show preemies face an increased risk of neurological and psychiatric problems that may be due to weakened connections in brain networks linked to attention, communication, and the processing of emotions.
“The brain is particularly ‘plastic’ very early in life and potentially could be modified by early intervention,” says principal investigator Cynthia Rogers, assistant professor of child psychiatry at Washington University in St. Louis.
“We usually can’t begin interventions until after symptoms develop, but what we’re trying to do is develop objective measures of brain development in preemies that can indicate whether a child is likely to have later problems so that we can intervene with extra support and therapy early on to try to improve outcomes.”
One of every nine infants in the United States is born early and, thus, with increased risk of cognitive difficulties, problems with motor skills, attention deficit-hyperactivity disorder (ADHD), autism spectrum disorders, and anxiety.
To get a better picture of how premature birth affects the brain, researchers used functional magnetic resonance imaging and diffusion tensor brain imaging to compare 58 babies born at full term with 76 infants born at least 10 weeks early. Each full-term baby was scanned on his or her second or third day of life. Each premature baby, meanwhile, received a brain scan within a few days of his or her due date.
Some key brain networks—those involved in attention, communication, and emotion—were weaker in premature infants, offering an explanation for why children born prematurely may have an elevated risk of psychiatric disorders.
“We found significant differences in the white matter tracts and abnormalities in brain circuits in the infants born early, compared with those of infants born at full term,” Rogers says.
Follow the babies
White matter tracts in the brain are made of axons that connect brain regions to form networks. The researchers also found differences in preemies’ resting-state brain networks, particularly in a pair of networks previously implicated in learning and developmental problems.
Among these resting-state networks is the default mode network, which tends to be most active when people are least active. The greatest differences between full-term and preterm babies were seen in this network and in the frontoparietal network. Both encompass brain circuits associated with emotion and previously have been linked to ADHD and autism spectrum disorders.
These brain circuit abnormalities likely contribute to problems that materialize as the children get older.
To see whether that’s true, the researchers are continuing to follow the babies, having completed follow-up evaluations when the children reached age 2, and for some, again at age 5. The researchers plan another series of brain scans in a few years as the original study participants reach the ages of 9 or 10.
“We’re analyzing the data we’ve already gathered, but we want to bring the children back when they are 9 or 10 and continue to follow their development. We want to look at the evolution of brain development in full-term versus preterm babies, and we want to know how that may affect who is impaired and who is not.”
That information may help doctors and scientists target abnormalities in the brains of preterm babies and, potentially, change the course of their development.
The researchers presented their findings at at Neuroscience 2015, the annual scientific meeting of the Society for Neuroscience.
The National Institute of Mental Health, the National Institute of Neurological Disorders and Stroke and the Eunice Kennedy Shriver National Institute of Child Health and Human Development, of the National Institutes of Health funded the work. Additional funding comes from the McDonnell Center for Systems Neuroscience, the Child Neurology Foundation, the Cerebral Palsy International Foundation and the Dana Foundation.