The time babies spend in the womb is far from idle. The brain is changing more rapidly during this time than at any other time in development.
According to koodakpress، It is an active time for the fetus to grow and explore, and of course connect to its mother. And new evidence from in-utero fetal brain scans shows, for the first time, that this connection directly affects brain development: A mother’s stress during pregnancy changes neural connectivity in the brain of her unborn child.
“It has long been thought that the stress of a mother during her pregnancy may imprint on the brain of her developing child,” says Moriah Thomason of Wayne State University who is presenting this new work at the 25th meeting for the Cognitive Neuroscience Society in Boston today. “Despite the clear importance of this time frame, we presently possess very little understanding of how functional macroscale neural networks build during this precious time in human life, or the relevance of this to future human health and development.”
This prenatal work is part of a growing body of research to better understand how the human brain develops across its lifespan, from fetus to old age. “We are interested in how a human brain constructs over time to become the adult brain,” says Nim Tottenham of Columbia University, whose work focuses on identifying sensitive periods of brain development from childhood into adolescence. She is chairing a session on new findings in brain development at the CNS meeting: “The talks aim to bridge across the very long brain development that gives rise to mature functioning.”
Seeing the changing fetal brain
Research in newborns and older children to understand prenatal influences has been confounded by the postnatal environment, Thomason explains. But recent advancements in fetal imaging allowed her and her team to gain insight into a critical time period in brain development never previously accessible.
Using fetal resting-state fMRI, they examined functional connectivity in 47 human fetuses scanned between the 30th and 37th week of gestation. The researchers recruited the participating mothers from a low-resource and high-stress urban setting, with many reporting high-levels of depression, anxiety, worry, and stress.
They found that mothers reporting high stress had fetuses with a reduced efficiency in how their neural functional systems are organized. It is the first time, imaging has shown a direct influence of maternal stress on fetal brain development, independent of influences of the postnatal environment.
“The major thrill is that we have demonstrated what has long been theorized, but not yet observed in a human, which is that the stress of a mother during her pregnancy is reflected in connectional properties of her child’s developing brain,” Thomason says. The data suggest that the brain does not develop in a sequence from simplest systems (e.g., vision, motor) to more complex high-order systems, but perhaps instead first develops the areas that will be most critical in bridging across systems.
The researchers found that the cerebellum played a central role in the observed effects, suggesting it may be especially vulnerable to the effects of prenatal or early life stress. The cerebellum has the highest density of glucocorticoid receptors, which are involved in stress responses, than any other place in the brain. Thomason and her team plan to further investigate this as a possible mechanism for the stress responses they observed.