How poverty changes a mother’s brain and her baby’s as well

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7min 12sec
Photo: poverty stress affects brain mri prep
Teryn Wilkes, MRI technologist, prepares a new mother for entering the MRI scanner that will scan her brain as she looks at images and listens to sounds like baby cries.

In our reporting on children in poverty in Colorado, we keep coming across research about how growing up poor can actually change a child's brain. As it turns out one of the leading researchers in the country on this is based at The University of Denver. Assistant professor Pilyoung Kim directs the Family and Child Neuroscience Lab and she's looking at how chronic stress and poverty gets into the brain's of new moms.

The job of parenting is so hard, "actually it’s pretty amazing that a lot of us are willing to do it," says Kim. She studies how poverty and stress influence brain development. Kim's especially interested in the way chronic stress may disrupt these adaptive changes in the brain and in turn, increase risk for post-partum depression and harsh parenting.

One of the reasons people have babies, she says, is because they find the emotional connection with their babies so rewarding. But for mothers to feel that emotion, their brain has to undergo big changes. Studies show it actually grows and rewires, particularly in the regions known as the "reward circuits."

"It’s the same circuit that responds to all things rewarding, like drugs, sex, food, but that same circuit responds to baby as well, and particularly strongly during the early post-partum period," says Kim. That allows a mother to regulate emotions better, to be less reactive to stress and more sensitive to her infant.

To understand how everyday stress influences first-time mothers, Kim has researchers visit mothers' homes within six months of birth. Mothers are recruited from the community including the programs, Women, Infant, and Children (WIC), Prenatal Plus, and Nurse Family Partnership (NFP) programs.

Lots of spitting

Bella Brown is a first-time mom. Her baby girl is about three months old. So far it’s been, "fun, exciting an exhausting, every day is a learning experience," she says. "Getting to know her cues. As soon as things become consistent, it all changes again."

Brown -- not her real name to protect her anonymity in Kim's study -- recently welcomed Kim’s team into her house. Her baby is alert and happy -- a great relief to her mother, who alternates between cuddling her and letting her sway in a rocker.

"I’m happy she’s in a good mood," she says.

Brown answers a list of questions: how much money the family makes, how stressed she’s felt in the past few days, what her childhood was like. She talks about living with her longtime boyfriend -- their income is stable, but they live paycheck to paycheck, and in the past, Brown's had to use a food bank to make ends meet.

Then Brown has to spit -- a lot -- over the next few hours, at the researchers' request.

Photo: poverty stress affects brain saliva
Lindsay Blanton, a research assistant with the Family and Child Neuroscience Lab at the University of Denver, records saliva samples from a new mother.

They will measure the spit’s cortisol, a stress hormone, and oxytocin, a hormone that fuels maternal bonding. They use a decibel reader to record how loud the house is. They videotape mom and baby interacting, which reveals a lot.

Research shows the link between poverty and post-partum depression is strong. The question is how that sometimes affects a mother’s emotional bond with her baby. In videotapes of these interactions, Kim sees a range of reactions.

"We have seen mothers who did not know how to interact with her baby, so she might focus on emails on phone – in the context when we were asking her to interact with baby - to the mothers who had constant interactions, affectionate touch, mutual gaze, a lot of singing," she says.

The home visits help researchers understand why, when faced with taking care of so many unpredictable problems, some parents may find it challenging to also provide good care to their children.

Brown is attentive and affectionate with her baby. She has struggled in the past with anxiety and depression and she says her mood has been up and down.

"Fortunately I missed out on the full-fledged post-partum depression, but definitely stressful days stressful nights, there’s definitely fear and anxiety but at the same time I consider myself very blessed, very lucky, this one is just a joy to be around, so that definitely counter balances a lot of the negative emotions," Brown says.

Into the scanner

Two days later, Brown is rolled into a magnetic resonance imaging scanner on the University of Colorado Boulder campus.

Technicians watch Brown's brain react on a screen to a series of images that are flashed before Brown -- some distressing, like angry faces, some happy, like drooling babies. She also listens to dozens of recordings of baby cries -- some of her own baby, some not.

Photo: poverty stress affects brain mri session
Teryn Wilkes, MRI technologist and Christana Congleton, a research assistant with the Family and Child Neuroscience Lab, collect brain images of a new mother. The images record minute changes in blood flow in different regions of the brain to help researchers understand how stress affects new mothers.

Kim says a baby's cry is a powerful stimulus. "It really, really strongly activates the brain regions involved in parenting," she says. "It really makes parents feel like, ‘I got to respond to this.'"

The scanner collects an image of Brown’s entire brain every 2300 milliseconds.

"What we’re measuring is those little minute changes in blood flow in one little area of the brain at a time," says technician Teryn Wilkes. The changes in brain flow tell researchers which parts of the brain are ‘activating’ or responding.

How your brain handles stress

Two parts of the brain that are strongly connected and central to stress management are the amygdala and the prefrontal cortex. The amygdala responds to threats.

"In an instant, the amygdala will fire up and tell other brain regions , saying ‘danger danger’ have to react immediately and hopefully appropriately," says Kim.

Then the prefrontal cortex enters the picture, saying, "OK calm down, we need to make a decision," she says.

In healthy brains, the prefrontal cortex calms the amygdala down. In someone who is really stressed, the prefrontal cortex isn’t able to calm it down so that everyday life feels stressful. In new moms who are extremely stressed or depressed, they may be less sensitive to her child's cry and have a harder time developing an emotional bond.

Typically, new mothers who hear their baby cry show increased activation in a brain region that plays an important role in reward, which allows them to be sensitive to the baby's cry. Kim says preliminary, unpublished data shows new mothers who feel depressed have lower levels of activation in this region after hearing their baby cry.

How your mother raised you is key

Brown calls her childhood rough. She knew about her family's money trouble at a young age. But she says her mother was caring and nurturing. Research is finding this is key. If a mother isn’t warm and caring, when the child grows up, studies find they may repeat that style of parenting.

"For example, if my mother was not very warm and caring, it actually changes gene expressions in my brain, in a brain region that’s very, very critical for maternal instinct," explains Kim. "So when I become a mother myself, that brain region will not work as effectively so I may repeat the same type of parenting style."

Photo: poverty stress affects brain pilyoung kim
Dr. Pilyoung Kim of the University of Denver is studying how poverty and chronic stress disrupts brain rewiring in first-time mothers.

Brown already carefully avoids letting her baby experience any stress she may be feeling.

"If I’m stressed, if I’m crying, even if I’m not showing it, I don’t want her to be exposed to it," she says. "I try to walk away, do deep breathing, take a glass of water, take a walk with her. Do whatever I need to do to get myself into a good state while dealing with her feeding her or hands on play."

And that’s a good thing.

The impact on children

Kim, the neurologist, also studies how stress changes a child’s brain as they grow and struggle to cope. There’s not enough evidence to make conclusions about how stress works in a child’s brain. But there are studies on how stress impacts a child’s ability to learn.

Researchers have demonstrated that certain environments, like when children who have reported living in crowded conditions or having conflict in the house "can actually diminish a child’s ability to learn, for example vocabulary and languages because they’re just so many sounds and information they have to filter out," Kim says.

"Living in poverty, experiencing, high levels of stress, can actually directly impact the function of brain areas that are involved in learning," she says.

Kim hopes to eventually isolate what kinds of stress associated with poverty have the most significant impact on the brain. Perhaps then, she says, experts and policy makers can target more precise interventions and treatments.

Ultimately she hopes her research, which is funded by the National Institute of Child Health and Human Development, will help remove negative labels placed on parents and children in poverty. It’s not simply that children may have difficulty regulating emotions or a parent may struggle with being responsive to their child, Kim says.

"I would think it’s helpful for people to understand that it’s not just because children were not making enough effort, or parents were not making enough effort," she says.

Instead, they’re up against changes in the brain that make their challenges even harder to overcome.

Tomorrow, we continue our series on poverty in the brain by looking at what can be done about it.