Summary: A new study reports the in utero environment can impact teenage brain development, contributing to problems with cognitive processing and emotional regulation.
Source: Concordia University.
Factors such as placement in the womb and access to nutrition impact cortical structure.
A new study shows that what happens to a fetus in the womb can affect the brain later in life.
In a paper recently published in Human Brain Mapping, a team of researchers from the Quebec-based Research Unit on Children’s Psychosocial Maladjustment shows how the in utero environment can play a role in the development of brain processes.
For the study, Linda Booij, associate professor of psychology in Concordia’s Faculty of Arts and Science and a researcher at Sainte-Justine Hospital Research Center, worked with researchers* from various institutions in the province of Quebec.
The team followed pairs of genetically identical twins from birth into their teenage years. They measured the twins’ weight at birth to assess whether different environmental factors had affected them while in the womb.
What they found is that the in utero environment was linked to the development of the cortex, a part of the brain that has many functions including regulating emotions and is involved in various cognitive abilities.
Size matters
Because twins share a prenatal environment, the fetuses have many environmental characteristics in common, like gestational age and the mother’s lifestyle. However, when they’re born, they can still differ in birth weight.
“Since the twins in our study are genetically identical, this difference in birth weight must be due to specific factors acting in utero,” Booij explains.
“For instance, one fetus might have a better placement in the womb or better access to nutrition.”
Previous research has shown that birth weight is a predictor of the way the brain develops. In the present study, Booij and her colleagues found that within genetically identical twin pairs, variations in birth weight were related to differences in the structure of the cortex, an association that cannot be explained by the genetic code in this case.
Brain structures
The researchers followed the twin pairs through to adolescence, conducting brain imaging to study the structure of the cortex in a subgroup of 52 pairs. They also collected DNA to study epigenetics — changes in the activity of how a gene is expressed through environmental experiences, rather than alteration of the genetic code itself.
“By the time our participants had reached teenagehood, differences in brain volume were present in the cortex, which is where much of our regulation of emotions and cognitive processes takes place,” says Booij, who is now also affiliated with Concordia’s PERFORM Centre.
“Interestingly, twins with large differences in birth weight and cortical structure also had epigenetic differences. This means that what happens in utero may affect a person’s brain development by the time they reach their teen years, and that epigenetic processes may play a role in this relationship.”
Booij and her colleagues hope that this study will shed more light on the specific role of early environmental influences on brain development, gene expression and emotional regulation.
“Our results will hopefully contribute to a better understanding of possible ways to foster optimal early brain development and prevent emotional and cognitive problems in youth.”
Kevin F. Casey, Melissa L. Levesque, Moshe Szyf, Elmira Ismaylova, Marie-Pier Verner, Matthew Suderman, Frank Vitaro, Mara Brendgen, Ginette Dionne, Michel Boivin, Richard E. Tremblay
Funding: Partners in research: This study was made possible by Sainte-Justine Hospital, the Canadian Institutes of Health Research, the Fonds de recherche du Québec-Santé, the Canada Research Chair program, the Fonds Québecois de la Recherche sur la Société et la Culture, the Social Science and Humanities Research Council of Canada, the National Health Research Development Program, Université Laval and Université de Montréal.
Source: Cléa Desjardins – Concordia University
Image Source: NeuroscienceNews.com image is in the public domain.
Original Research: Abstract for “Birth weight discordance, DNA methylation, and cortical morphology of adolescent monozygotic twins” by Kevin F. Casey, Melissa L. Levesque, Moshe Szyf, Elmira Ismaylova, Marie-Pier Verner, Matthew Suderman, Frank Vitaro, Mara Brendgen, Ginette Dionne, Michel Boivin, Richard E. Tremblay, and Linda Booij in Human Brain Mapping. Published online December 29 2016 doi:10.1002/hbm.23503
[cbtabs][cbtab title=”MLA”]Concordia University “In Utero Conditions Can Affect Teen Brain Development.” NeuroscienceNews. NeuroscienceNews, 24 January 2017.
<https://neurosciencenews.com/teen-brain-development-pregnancy-6001/>.[/cbtab][cbtab title=”APA”]Concordia University (2017, January 24). In Utero Conditions Can Affect Teen Brain Development. NeuroscienceNew. Retrieved January 24, 2017 from https://neurosciencenews.com/teen-brain-development-pregnancy-6001/[/cbtab][cbtab title=”Chicago”]Concordia University “In Utero Conditions Can Affect Teen Brain Development.” https://neurosciencenews.com/teen-brain-development-pregnancy-6001/ (accessed January 24, 2017).[/cbtab][/cbtabs]
Abstract
Birth weight discordance, DNA methylation, and cortical morphology of adolescent monozygotic twins
Background
Several studies have shown that the in utero environment, which can be indexed by birth weight (BW), is associated with cortical morphology in adolescence and adulthood. Work in monozygotic (MZ) twins suggests that this association is driven by non-shared environmental factors. This correlation could be the result of in utero impacts on DNA methylation. The aim of the present study with MZ twins is to replicate the association between discordance in BW and brain morphology and test whether discordance in DNA methylation mediates this relationship.
Methods
One hundred and four adolescent MZ twins (52 pairs, of which 42% were male pairs) who have been followed regularly since birth underwent T1 weighted structural MRI, and epigenome-wide assessment of DNA methylation from saliva at age 15.
Results
Co-twins had very similar measures of DNA methylation and cortical morphology. Higher BW members of a twin pair had increased total cortical surface area, and decreased cortical thickness compared to their lower BW sibling. BW Discordance was positively associated with both cortical surface area and cortical volume discordance. Genes involved in neurodevelopment were tentatively identified as mediators of both the BW – cortical volume, and BW- cortical surface area relationships.
Conclusions
The association between BW and cortical morphology in adolescence appears to be attributable to in utero environmental effects, and DNA methylation may play a role in mediating this relationship.
“Birth weight discordance, DNA methylation, and cortical morphology of adolescent monozygotic twins” by Kevin F. Casey, Melissa L. Levesque, Moshe Szyf, Elmira Ismaylova, Marie-Pier Verner, Matthew Suderman, Frank Vitaro, Mara Brendgen, Ginette Dionne, Michel Boivin, Richard E. Tremblay, and Linda Booij in Human Brain Mapping. Published online December 29 2016 doi:10.1002/hbm.23503
