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CIFAR researchers author new volume that changes our understanding of the early years of human life

Tuesday, October 9, 2012

For the first time, scientists have amassed a large collection of research that looks “under the skin”, to examine how and why experiences interact with biology starting before birth to affect a life course.

CIFAR researchers author new volume that changes our understanding of the early years of human life
Published today in the Proceedings of the National Academy of Sciences (PNAS), the special volume titled ‘Biological Embedding of Early Social Adversity: From Fruit Flies to Kindergartners’ sets out an emerging new field of the developmental science of childhood adversity.

Authored largely by researchers in CIFAR’s Experience-based Brain & Biological Development program and edited by co-directors W. Thomas Boyce (University of British Columbia) and Marla Sokolowski (University of Toronto), the volume was inspired by an Arthur M. Sackler Colloquium co-hosted by CIFAR and the National Academy of Sciences in December, 2011.

“CIFAR's multidisciplinary and international program in early childhood development is transforming our understanding of how early life experiences affect the development of the brain and in so doing set a lifelong trajectory,” says Dr. Alan Bernstein, CIFAR President & CEO. “This research is providing the scientific basis for public policy concerning the critical window we have to provide the optimal conditions that will enable our children to grow up to be well-adjusted, well-educated and productive individuals.”

The volume is a multidisciplinary collection of 25 thought-provoking papers that will influence a broad range of scientific inquiry: from molecular genetics, evolutionary biology and neuroscience to social and behavioural science, epidemiology and social policy. The implications of the research are far reaching, from new approaches to learning and language acquisition, to new considerations for the health effects of social environments affecting large populations, and policies for early childhood care and education.

“This is the first volume of collected research to provide such a substantial and comprehensive picture of the interaction between experience and biology in the early years,” says Dr. Sokolowski. “Brain and genetic development are extraordinarily intricate and complex, and so by approaching this question from multiple angles, we’re able to reveal a convergence on a number of themes, giving us new insights and an understanding of a greater whole, which now sets more clearly a direction for research to come.”

A few highlights:

From the lab of Fellow Michael Meaney (McGill): Scientists have provided evidence that socioeconomic status (SES) affects family function and the development and function of brain regions that are critical for attention, learning and memory. Dr. Meaney’s lab looks into how parenting produces lasting effects on cognitive and emotional development. His lab examined development in rats and found parental influences on the chemical, or 'epigenetic', signals that control the activity in the brain of genes that influence the connections between brain cells as well as learning and memory. In adult animals that were licked more frequently by their mothers the epigenetic signals enhanced the activity of genes associated with learning and memory. These findings reveal that social influences during early life affect the activity of genes that affect the structure and function of brain regions critical for cognitive capacity.

From the lab of Fellow Takao Hensch (Harvard): Given that music is a powerful tool for probing and promoting brain development, Dr. Hensch and his collaborators exposed young mice to music and discovered a critical period between 15 and 24 days of life when they could change the mice's innate preference for a silent shelter to a preference for shelter with music. Typically, this preference cannot be altered in adulthood. However, the team then treated adult mice and were able to show that a key brain region could be re-wired to have a preference for music in later adult years. His results point to molecular factors that emerge after early critical periods of plasticity and can be manipulated in adulthood – the first evidence that a juvenile form of higher cognitive behavior can be restored. This clearer picture of molecular mechanisms in early development is critical to eventually treating complex, life-long disorders of the brain, such as autism or acute anxiety.

From the lab of Fellow Thomas Boyce (University of British Columbia): Guided by animal models of hierarchy and an understanding of the health effects of SES, Dr. Boyce and his team examined the behavioral development of children in a kindergarten classroom hierarchy. The study found that children in subordinate roles had more depressive behaviors and inattention, fewer good friends and diminished academic ability. The study found that subordination was compounded by low SES – the children with low SES had the lowest levels of prosocial behaviors. Importantly, the study found that teachers who utilized child-centred teaching practices to create better classroom climates were able to diminish some of the adverse effects of stratification. The study suggests that socioeconomic gradients in health and development are the products of more than simply differences in access to money, material goods, medical care, or nutrition. When taken with our growing understanding of the importance of the first five years of life, this research renders even more crucial the need to provide egalitarian and supportive early childhood settings.

From the lab of Fellow Janet Werker (University of British Columbia): Janet Werker and her researcher collaborators at University of British Columbia, the Child & Family Research Institute (CFRI) at BC Children’s Hospital and Harvard University studied babies belonging to three groups of mothers – one being treated for depression with serotonin reuptake inhibitors, one with depression not taking antidepressants and one with no symptoms of depression. By measuring changes in heart rate and eye movement to sounds and video images of native and non-native languages, the researchers calculated the language development of babies at three intervals, including six and 10 months of age. The heart rate response of unborn babies at age 36 weeks to languages was also measured. Their study is the first to show that maternal depression and its treatment can accelerate babies’ ability to attune to the sounds and sights of their native language, thereby affecting the timing of language development in babies.

CIFAR researchers reporting in the PNAS special edition

  • Ronald G Barr (University of British Columbia): Abusive head trauma: Preventing a failure of normal caregiver-infant interaction.
  • W. Thomas Boyce (University of British Columbia): Social stratification, classroom 'climate' and the behavioral adaptation of kindergarten children.
  • David F Clayton (Queen Mary, University of London): The impact of experience-dependent and -independent factors on gene expression in songbird brain.
  • Lia C. H. Fernald (University of California at Berkeley): Socio-economic gradients in child development in very young children: Evidence from India, Indonesia, Peru and Senegal.
  • Russell D Fernald (Stanford University): How does social information change the brain?
  • Takao K Hensch (Harvard): A critical period for acoustic preference in mice.
  • Clyde Hertzman (University of British Columbia): Biological embedding: Putting the concept in perspective.
  • Michael S Kobor (University of British Columbia): Biological and environmental predictors of variable DNA methylation in a human community cohort.
  • Bryan Kolb (University of Lethbridge): Experience and the developing prefrontal cortex.
  • Joel D. Levine (University of Toronto, Mississauga): Social structures depend on innate determinants and chemosensory processing in Drosophila.
  • Michael J. Meaney (McGill University and Douglas Hospital Research Centre): Variations in postnatal maternal care and the epigenetic regulation of Grm1 expression and hippocampal function in the rat.
  • Michael Rutter (King's College London): Achievements and challenges in the biology of environmental effects.
  • Marla B Sokolowski (University of Toronto): Gene-environment interplay in Drosophila melanogaster: Chronic food deprivation in early-life affects adult exploratory and fitness traits.
  • Moshe Szyf (McGill University): Conserved epigenetic sensitivity to early life experience in the rat and human hippocampus.
  • Janet F. Werker (University of British Columbia): Prenatal exposure to antidepressants and depressed maternal mood alter trajectory of infant speech perception.

Click here to see all Sackler Colloquium articles in the PNAS special edition of October 16, 2012.
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