Good Parenting Triumphs Over Pre-Natal Stress

Stress Hormone in Womb Predicts Poorer Cognitive Development, but Loving Care Can “Undo” It.

A mother’s nurture may provide powerful protection against risks her baby faces in the womb, according to a new article published online today in the journal Biological Psychiatry. The research shows that fetuses exposed to high levels of stress hormone – shown to be a harbinger for babies’ poor cognitive development – can escape this fate if their mothers provide them sensitive care during infancy and toddler-hood.

The new study represents the first, direct human evidence that fetuses exposed to elevated levels of the stress hormone cortisol may have trouble paying attention or solving problems later on. But what may be more intriguing is the study’s second finding – that this negative link disappears almost entirely if the mother forges a secure connection with her baby.

“Our results shape the argument that fetal exposure to cortisol – which may in part be controlled by the mother’s stress level – and early caregiving experience combine to influence a child's neurodevelopment,” said study author Thomas O’Connor, Ph.D., professor of Psychiatry and of Psychology at the University of Rochester Medical Center, and director of the Wynne Center for Family Research. “If future studies confirm these findings, we'll need to not only engineer ways to reduce stress in pregnancy, but we’ll need to also promote sensitive caregiving by moms and dads.”

For the study, researchers recruited 125 women at an amniocentesis clinic in an urban maternity hospital, taking a sample of their amniotic fluid so that stress hormones in it could be measured. The mothers were at 17 weeks gestation on average; only mothers with normal, healthy pregnancies and subsequent deliveries were followed.

When their children reached 17 months of age, researchers administered a Bayley infant developmental scale test, which relies on puzzles, pretend play, and baby “memory” challenges to gauge youngsters’ cognitive development. They also observed the baby and mother using the Ainsworth “Strange Situation” test, which judges childrearing quality, categorizing mom-baby pairs as either showing secure or insecure attachment to each other (watch the YouTube video of a sample of this sort of test in action below).

With cortisol levels, relationship quality results, and cognition scores in hand, researchers analyzed how the first two measures might influence the third. Indeed, for children showing “insecure attachment” to their mothers, a high prenatal cortisol level was linked with shorter attention spans and weaker language and problem-solving skills. But interestingly, for kids who enjoyed secure relationships with their moms, any negative link between high prenatal cortisol exposure and kids’ cognitive development was eliminated.

“This is such refreshing news for mothers,” O’Connor said. “Pregnancy is an emotional experience for many women, and there is already so much for mothers to be careful of and concerned about. It’s a relief to learn that, by being good parents, they might ‘buffer’ their babies against potential setbacks.”

Study Spawns Future Questions

O’Connor goes on to note a couple important nuances of the study. The first is that the amniotic (in-utero) cortisol studied could result from two sources, and it’s hard to pinpoint which. It might, for instance, be passed along the placenta from an anxious mother to her unborn baby – or it could be created and excreted directly by a stressed fetus itself.

“While many large-scale studies have observed that prenatal stress may influence child development, our particular study sheds some light on the 'how',” O’Connor said. “Still, much more research is needed to better pinpoint the exact mechanisms behind a mother ‘transferring’ her stress to her unborn baby.”

This study plays into the much larger theory of “fetal programming,” which suggests that events in the womb may prime the developing child for long-term health and developmental outcomes. Past studies, for instance, have found a pregnant mother’s diet can sway a child’s long-term risk for heart disease, diabetes and obesity. Along with diet, prenatal stress has emerged as another large-looming factor in such programming.

“Our results support this emerging theory,” said London-based study co-author, Vivette Glover, Ph.D. “In neurology, the idea emerging is that unborn children sense their mothers’ stress hormone levels, programming them for greater watchfulness. We're trying to determine whether or not that sensitivity comes with greater anxiety during childhood, and if so, what we can do about it.”

The team’s next study will revisit these same children when they turn 6; at that point, researchers hope to give the group a battery of more definitive tests to see how the interplay between in-utero cortisol levels and sensitive parenting pans out in the long-term. Those tests would include imaging studies of the children’s brains, looking to see if the higher cortisol levels may be linked to anatomical changes.

The study was supported by grants from the March of Dimes and the National Institute of Mental Health, part of the National Institutes of Health.

Campus Child Care Needed ForStudent-Parents

Brent McBride, a professor of human development at Illinois, says the college drop-out rates of traditional undergraduates who are also full-time parents is a growing problem in the U.S.

The lack of affordable, high-quality on-campus day care programs that cater to undergraduate students who double as parents is a stealth issue that has the potential to harm both the student-parent and the child, says a University of Illinois expert in early childhood education.

According to Brent McBride, a professor of human development at Illinois, the college drop-out rates of traditional undergraduate students – college freshmen who have just transitioned from high school – who are also full-time parents is a growing problem in the U.S., one that’s further exacerbated by the lack of acceptable child care options for students pursuing a bachelor’s degree.

“The typical scenario is a young 18- to 20-year-old woman who’s away from home for the first time, separated from her familial support system, and may be in a difficult relationship with their partner,” McBride said. “It’s mostly a hidden issue, and that makes it that much worse for those student-parents, because it tends to make them feel that much more isolated. It’s just a difficult situation all around.”

Among the challenges student-parents face are a lack of money, a lack of support and understanding, and the mounting pressure of familial responsibilities.

Finding affordable child care is another big challenge student-parents face, but McBride, who also is the director of the university’s Child Development Laboratory, believes campus-based support programs, including affordable, high-quality campus day care, may provide the assistance that student-parents need to complete college while successfully raising a child.

With an on-campus day care center that’s welcoming of student-parents, “You take one big headache out of the equation,” McBride said.

“What we’ve found and what the literature supports is that traditional undergraduate students who are suddenly thrust into this role of parent aren’t prepared for all the responsibilities being a full-time parent entails,” he said. “They’ve been focused on social relationships and educational endeavors, but they haven’t thought about being a parent with a newborn baby. Having an on-campus day care program that welcomes and understands the demands on student-parents provides a support mechanism as well as a way for them to learn parenting skills.”

Affordable campus child care is also crucial to the success of student-parents from a personal developmental standpoint.

“The student-parents themselves are also at a very vulnerable stage of their own personal development,” McBride said. “They’re in that identity exploration phase where they’re transitioning to young adulthood, trying to figure out who they are, and are trying on different careers and roles for themselves.”

But with a baby in tow in addition to their full-time studies, student-parents often find themselves “tossed into an adult world with minimal preparation and minimal support for that change,” McBride said.

“Not only are they at risk for academic failure, they’re also severely at risk for personal problems because of that disruption of their own development,” he said. “That only amplifies the concern we have for these students.”

It should come as no surprise, then, McBride said, that student-parents are three times as likely as traditional undergraduates to drop out.

“If you’re a student-parent, you’re at greater risk of not succeeding at any type of institution of higher education simply because you’re a parent, and the hardships and hurdles are that much higher,” McBride said.

While their friends and peers are attending class, studying and completing homework assignments, student-parents must do all that plus raise a child.

“The vast majority of their peers are traditional undergraduate students, so there’s no organization to support them, and no way for them to congregate and seek out others in their situation,” he said.

The faculty at a traditional college or university is also usually in the dark about a student’s parental responsibilities outside of class.

“How are student-parents supposed to complete group assignments if they have to take care of a child? Not being able to participate in normal undergraduate activities only serves to further isolate them, which in turn leaves them at greater risk of dropping out and not earning a degree.”

Faced with choice between raising a child or pursuing a degree, McBride says student-parents usually have no choice but to dropout and forgo what many educators and economists see as a key component to long-term economic stability and mobility.

“The lifelong trajectory of these students is, once they transition to parenthood, they don’t finish school,” he said. “And with the economy the way it is, this is a very vulnerable demographic. Their job prospects are really hamstrung.”

Having an on-campus day care center for undergraduate student-parents not only benefits the student who eventually graduates with a bachelor’s degree, it also benefits the child.

“It helps the student-parent, because it’s one less ball that they have to juggle,” McBride said. “Trying to balance school and parenting is a tough thing to balance, especially if you’re a young single parent. But day care also benefits the child in multiple ways.”

Research overwhelmingly suggests that high-quality child care has a significant positive impact on the development of young children’s language and pre-math skills, along with other soft skills such as self-control, sociability and cooperative play.

A campus-based day care center could also leverage university resources easier than a commercial day care center.

“If there’s a language delay, for example, we can tap into campus experts in that area,” McBride said. “If there’s dysfunctional parenting, we can step in and make referrals to campus resources to help with parenting.”

Campus-based day care facilities also offer better quality controls than profit-oriented child care programs. Research consistently indicates that as much as 40 to 60 percent of all child care in the United States has been deemed sub-standard – “so sub-standard that it’s harming the child rather than helping,” McBride said.

“For better or for worse, the quality of community-based child care programs is not always what we would want it to be,” he said. “Having federal dollars being poured into something that’s less than optimal from the child care perspective, that could actually be to the detriment of the child, is not a good investment of taxpayer dollars.”

A good investment is one that’s made in human capital, so marginalizing someone who is unable to complete a college degree simply because of a child care issue is, from a social justice perspective, a tragic mistake to make, McBride said.

“If a person has the human capital to go to college, we’ve got to help them cultivate that potential,” he said. “We need to encourage parents to be good parents, to be productive members of society and to be able to provide for their children. If you take away the opportunity for higher education, they’re not going to be able to provide. We don’t want to take away those opportunities. The consequences are just too great.”

To help low-income undergraduate student-parents complete their studies, the Child Development Laboratory at Illinois is now accepting undergraduate student-parents and their children into the Child Care Access Means Parents in School (CCAMPIS) program.

Funding for the program was provided by a grant from the U.S. Department of Education.

Evolution of Neural Circuitry

James Rilling entered the University of Wisconsin in Madison as a pre-med major, following in the footsteps of three older brothers who are physicians. But an evolutionary biology class changed his plans.

"I thought the course was so powerful," says Rilling, associate professor of anthropology and the founder of Emory's Laboratory for Darwinian Neuroscience. "All societies have had a need to understand their origins. But they've made up myths to explain it, while evolutionary biology is trying to get at the true story."

Encouraged by his parents to pursue his passion, Rilling left the pre-med track to study the essence of human nature. "It's like the space program," he says. "We believe that we should be trying to understand the universe around us. I feel the same way about exploring the brain to learn who we are and how we got here."

The Milwaukee native came to Emory as a graduate student, drawn by the anthropology department's emphasis on human biology. "It's a definite strength," Rilling says, citing the department's access to Yerkes National Primate Research Center, and the quality of the faculty.

For his dissertation, Rilling used functional magnetic resonance imaging (fMRI) to compare the neuroanatomy of humans and 10 other primate species at Yerkes. The 1998 study was the first in-depth look at whether the human brain is merely a scaled-up version of the brains of other primates.

"We found that human temporal lobes are larger than you would expect for a primate of our brain size," Rilling says. "We've done subsequent work that shows this larger size is likely due to the evolution of language pathways in humans."

The study also found that the human prefrontal cortex is more convoluted than expected. "One of the things that causes these cortical folds is when strongly connected areas of cortex get pulled together. That could be the neural basis for our ability to integrate lots of different types of information," Rilling says, explaining that the prefrontal cortex is involved in functions like planning, decision-making, emotional regulation and working memory.

Rilling's Laboratory for Darwinian Neuroscience is a leader in the use of non-invasive imaging technology to compare the neuroanatomy of living primates.

Much previous work has focused on the gray matter of brains. Rilling's group is the only one in the world using diffusion tensor imaging (DTI) to compare the white matter connections of monkeys, humans and our closest relative, chimpanzees. White matter contains the fiber tracts that connect and "wire" the brain.

"We've discovered a difference in both the size and the trajectory of the fiber tract that runs between Wernicke's area in the left temporal lobe and Broca's area in the left inferior frontal cortex," Rilling says. Broca's area is involved in speech production and Wernicke's in understanding language. In humans, the pathway that connects the two areas is much more massive, and projects beyond Wernicke's area down to the ventral part of the temporal lobe.

"There's something special going on in the human brain with that pathway," Rilling says. "It's organized differently than in other primates."

The lab is also exploring the neural basis of human cognition and behavior. One of its studies showed that reciprocation in humans is tied to activation of a reward pathway in the brain. "The magnitude of that reaction correlated to how likely the person was to cooperate in the future," Rilling says.

When you cooperate and someone else fails to reciprocate, activation is found in the anterior insula, a brain region known to track visceral responses of the body.

Why are some people more cooperative than others? How does the brain change with age? What promotes social bonding and attachment? These are just a few of the many research questions the lab is tackling.

"We want to start to understand individual human differences in social behavior, at both the genetic and neurological levels," Rilling says. He adds that he's particularly interested in understanding why some men are more nurturing as fathers than others.

"It's important to have someone besides the mother involved in a child's care. I think one way that we could improve childhood development is to have more committed dads," says Rilling, who is married to a psychiatrist and hopes to one day become a father.

How Nerve Cells Grow

Max Planck Institute researcher decodes a molecular process that controls the growth of nerve cells.

Brain researcher Hiroshi Kawabe has discovered the workings of a process that had been completely overlooked until now, and that allows nerve cells in the brain to grow and form complex networks.

The study, which has now been published in the journal Neuron, shows that an enzyme which usually controls the destruction of protein components has an unexpected function in nerve cells: it controls the structure of the cytoskeleton and thus ensures that nerve cells can form the tree-like extensions that are necessary for signal transmission in the brain. (Neuron, February 11, 2010)

Fig.: In the brain of mice, which cannot produce Nedd4-1, the extensions of nerve cells are shorter and of much simpler construction (example top) than in the brain of normal mice (example bottom). Image: Hiroshi Kawabe

In order to be able to receive signals from other cells, nerve cells form complex extensions called dendrites (from the Greek ‘dendron’ meaning tree).

The growth of dendrites in the human brain takes place mainly during late embryonic and infantile brain development. During this phase, dendrites, with a total length of many hundred kilometres, grow from the 100 billion nerve cells in our brain. The result is a highly-complex network of nerve cells that controls all bodily functions - from breathing to complicated learning processes.

In order that this incredible growth phase of brain development does not lead to chaos, the growth of the dendrites must be accurately controlled. In fact, a large number of signal processes control the direction and the speed of dendrite growth by influencing the structure of the cytoskeleton, which is inside the growing dendrite and responsible for its shape and extension.

Hiroshi Kawabe has now discovered exactly how the growth of the cytoskeleton is controlled during the dendrite development.

Using specially bred genetically engineered mice, the Japanese guest scientist conducting research at the Max Planck Institute for Experimental Medicine, discovered that the Nedd4-1 enzyme is essential for regular dendrite growth.

Nedd4-1 is an enzyme that usually controls the degradation of protein components in cells by combining them with another protein called ubiquitin. The cell identifies these ubiquitinated molecules as "waste" and degrades them. In some cases, however, the ubiquitination does not lead to the degradation of the marked protein but changes its function instead.

Nedd4-1 prevents degradation of the cytoskeleton

Hiroshi Kawabe has now shown that the Nedd4-1 enzyme ubiquitinates a signal protein called Rap2, preventing it from initiating the dismemberment of the cytoskeleton and collapse of the dendrites.

"As long as Nedd4-1 is active, the nerve cell dendrites can grow normally," reports Kawabe. "In its absence, the dendrite growth comes to a standstill and previously formed dendrites collapse, with dramatic consequences for the function of nerve cell networks in the brain."

There are, however, probably a number of parallel operating signal paths which control dendrite growth. This explains why nerve cells can also form dendrites without Nedd4-1 - although significantly fewer - and shorter - in number. The Nedd4/Rap2/TNIK mechanism would then be only one of several that can partially compensate for each other.

Kawabe's discovery provides important new insight into the mechanisms which control the development of the brain. Scientists have long been aware that Nedd4-1 is one of the most prevalent ubiquitination enzymes in nerve cells and is produced with great frequency in the developmental phase when nerve cells grow and form their dendrites.

As Kawabe points out, the function of Nedd4-1 has already been investigated in dozens of studies. "But very little work has been carried out on its role in nerve cell development, which would have been the obvious thing to do. What is surprising is that no-one has investigated this before," says the Japanese biochemist. "