Cathi Propper, PhD, her research team at the UNC Brain and Early Experience Laboratory, and several others at UNC are exploring an area of biobehavioral health on which there has been little evidence gathered in children: the relationship between the gut microbiome and anxiety.

A new $3.6 million award from the National Institute of Mental Health (NIMH) supplements the BEE (Brain and Early Experience) Study – "A Mechanistic Study of the Association Between Poverty and Executive Functions in Early Childhood: Contributions of Early Brain Development and the Early Caregiving Environment" – which was originally funded by the Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD) in 2018 at $2.1 million. The BEE study specifically focuses on the influence of poverty on brain development and cognitive development in children to determine how prenatal experiences might influence development of children.

Propper is an advanced research scientist and the director of the Development Biobehavioral Core at the UNC Frank Porter Graham Child Development Institute. This new grant, "The Development of Gut Microbiota and Behavioral Inhibition in Childhood: The Role of Early Stress and Brain Development," allows Propper's lab to take their biobehavioral research even further for these participants to determine whether precursors to anxiety can be seen in gut health, and how that might impact a child's development.

"We have been following a sample of children from birth to age 3 to learn more about the effects of poverty on brain development, and this grant is going to allow us to follow them even longer. We've collected a variety of data over the first 3 years, but this particular grant will allow us to look closely at their gut microbiome," she says. "We know that gut microbiome has been related to brain development and anxiety behaviors, we have seen this in animal and adult studies, but we will be among the first to examine this association from pregnancy forward in humans."

To look at the different gut profiles in the children, the team starts collecting fecal samples from the mothers during pregnancy, and then from babies at six different ages to get multiple measures across time. They will look at the associations between the gut microbiome and behavioral inhibition from age 2 to 5 and use neuroimaging see how brain development plays a role in this relationship.

"We'll look at these data to see how the microbiome develops. Is the infant's microbiome similar to their mom's at birth? There is evidence to suggest that is the case. But, once babies start breastfeeding and then eating solid foods, it may change again. We're interested in the influence of the prenatal experience, genetics, nutrition, and the physical environment on its development."

Biobehavioral research, as done in the BEE Lab, is a research focus that has grown at FPG, especially as the Institute welcomed Director Ayse Belger, PhD, a professor and director of neuroimaging research in UNC's Department of Psychiatry, in 2018. Biobehavioral research looks at both biological and behavioral measures of health and how the two are interrelated in human function.

"For development, we know it's not just temperament or genetics that matter, but it's also not just the environment that matters." says Propper. "It's the interplay of all of these things and we are interested in how this sets children up for critical developmental outcomes in areas like school readiness and peer relationships."

Babies have their own intrinsic characteristics, like their physiological responses to stress, that can influence the way they engage with the environment or with the way caregivers react to them. Propper's lab looks at the specifics of these characteristics and these environments, and then how they coregulate each other as children develop self-regulation or behavioral skills.

Biobehavioral aspects have been often overlooked in research, says Propper, but these data can be especially revealing as researchers try to understand the experiences of children, especially when they're too young to communicate. Improvements in wearable technology that is lightweight and unobtrusive—often no more so than wearing a watch—makes it easier to take measurements of children's and mothers' biological processes in the caregiving environment.

"We can do noninvasive activities in the home to get natural observations of these processes without a lot of unnecessary or added equipment. For example, now we have equipment that is light and comfortable, like stickers, to measure stress levels. For young children, it gives you the kind of information that the child themselves can't, and that parents don't always know."

This kind of research may also aid health care providers as they offer advice to parents as their children reach developmental stages and milestones and strives to avoid one-size-fits-all solutions that might not work for all children.

"We are trying to learn more about what works best for different children based on their own intrinsic characteristics, which in the end will serve them better," says Propper.

Additional UNC contributors to this study include M. Andrea Azcarate-Peril, PhD, Departments of Medicine and Nutrition; Roger Mills-Koonce, PhD, School of Education; Margaret Sheridan, PhD, Department of Psychology and Neuroscience; Martin Styner, PhD, Department of Psychiatry; and FPG's Sabrina Zadrozny, PhD.