How the developing brain of a child who was internationally adopted may differ from a typical child’s brain and what interventions might help? Part 1: The Developmental Science

How might the developing brain of a child who was internationally adopted differ from a typical child’s brain and what interventions might help?

Part 1: The Developmental Science

This is part 1/4 in this series of blog posts.

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newbornMost parents are familiar with the nature vs. nurture debate about children– Are children’s qualities (personality, intelligence, etc.) innate, or are they determined by their life experiences?  This debate has taken on a more complex form in the last few decades.  It is no longer about nature OR nurture.  It is about how nature and nurture interact during different stages of development.  As an adoptive parent this issue hits close to home.

  • How do my child’s innate qualities (genetics) interact with the environment both pre-adoption and post-adoption? 
  • What can (or can’t) I do to change the impact of negative early life experiences?
  • What should I be prepared for in my child’s future based on his or her early life experiences?
  • Are there specific parenting or teaching strategies I can use to help my child be more successful?

Key concept #1:  Developmental Systems Theory and Epigenetics

Developmental systems theory is the predominant theory in research related to child development.  Development happens in structures or systems, each with its own function, and that development is driven by genetic, environment, and epigenetic factors.  Research has found that early childhood experiences are “biologically embedded,” meaning that experiences change the structure and function of the brain, which is the foundation for future development.  How this occurs is a combination of genetics, environment (the experiences of a person), and epigenetics (how the experiences of a person can change which gene gets expressed).

Epigenetics and biological embedding can be hard concepts to grasp, but they are critical to understanding a child’s development.  A person’s genes are like a set of instructions for his or her body.  In this instruction set, there are key points when the body is supposed to evaluate its environment/experiences to determine which set of instructions to follow.  A common example of epigenetics is a study done about the Dutch famine of 1944.  The amount of food available to a pregnant woman during different times in her pregnancy changed life-long characteristics of her child’s development related to growth and obesity.  The prenatal environment interacted with the child’s expression of his or her genes, and the genes continued to impact growth and obesity through the lifespan.  Going back to the analogy of the set of instructions, if you are a Dutch baby in 1944, your set of instructions told you go on genetic pathway X if famine was experienced and genetic pathway Y if normal nutrition was experienced.  Once the genetic pathway was chosen, it was the foundation for future development.  If you are interested in learning more about epigenetics, I recommend this article, Beyond DNA: Epigenetics, by Nessa Carey.epigenetics example

Key concept #2: Plasticity and Critical Periods

All brains are plastic, meaning they are changeable.  The changes occur at every level, from the basic cell (neuron), how the cells communicate and connect (neurotransmitters and synaptic connections), and how the cells form structures and pathways.  The structure and function of the brain adapts based on stimulation from the environment.  For example, if a person learns to play the trumpet (which involves 3 fingers on the right hand playing the valves), after much practice, skills improves and neural changes occur.  A brain scan will show there are more neural connections and more brain activity related to use of those 3 fingers than prior to learning the trumpet.

Children’s brains are highly plastic, with the theory being they are most plastic early in life.  There appear to be critical periods (or sensitive or vulnerable periods) of time for certain areas of development in which environmental influences can have a permanent effect on the physiological functioning of the brain.  In the previous example of the Dutch famine, there was a very specific time period of development in which the environmental influences affected the development of growth and obesity.  Given that there are countless different systems developing at different times and interacting in ways that science is only being to understand, there is no way to know exactly when all the critical periods occur.  What is most relevant to the discussion of internationally adopted children is that there appear to be systems developing related to handling emotions and stress that have a critical period in early childhood, and these systems are highly related to long-term success for children.

Key concept #3: Neural Pathway for Stress Response

brain stress pathwaysThere are distinct neural pathways for responding to stress.  The limbic system processes and stores the stressful events (amygdala –>hippocampus), and then connects to the prefrontal cortex to interpret (hippocampus –> prefrontal cortex).  This causes a whole body reaction, including stress hormones, increased heart rate and blood pressure, more blood flow to the brain, and vigilance/fear.

This system has a critical period early in life in which life experiences shape how this neural pathway will work for lifelong patterns of emotionality and stress response.  This is believed to happen through the model of epigenetics and biological embedding.  Research has shown that chronic stress early in life changes the structure and function of this pathway, leading to future problems with emotional regulation and cognition.  More specifically, there are two main pathways that are susceptible to change: hypothalamic-pituitary-adrenal (HPA) axis and the sympathoadrenal medulla (SAM) pathways.  The SAM is responsible for the flight or fight response.  The HPA axis controls cortisol and other hormones that promote balance in the stress response system.  These pathways are constantly trying to achieve a balance called “allostasis.”  In an ideal setting, a child feels stress and turns to a caregiver for support.  The child feels safe, so the stress reaction is stopped and the SAM and the HPA axis pathways stabilize the response, allowing allosis (balance) to be achieved.  Chronic stress (or lack of caregiver support while stressed) can cause “allostasis load” which disrupts the balance.  This protects a person in the immediate harsh environment, but disrupts the body and brain’s ability to respond effectively to stress.  The long term effects of allostasis loading have been found in changes in metabolic functioning, immune response, emotional and social regulation, and cognitive functioning and learning.Epigenetics of stress pathway

Summary: Early life stress –> biological changes –> modifies how the pathway/system matures and responds (biological embedding) –> long term effects on emotional regulation and cognition.

The neural pathway for stress response has a critical period in which it is sensitive to social interaction and maternal care.  The theory is that maternal care helps infants adapt appropriately to stress, strengthening neural pathways for emotional regulation and cognitive responses to stress.  Research has shown that social deprivation early in life creates vulnerability to problems with emotional regulation, mental health, and cognition. This has specifically been found in children who have experienced early life trauma and deprivation, such as children adopted from institutions internationally.

Implications for internationally adopted children?

China SWI CribsResearch has found increased stress responses in children adopted internationally, both at a basic level (cortisol in the saliva) and behavioral level (increased rates of behavioral and learning problems). This has been a robust finding both when children are newly home and after spending many years in a nurturing home.  While impossible to prove definitely, it is likely that early life experiences/environments interacted with a child’s genetics to create a biologically embedded stress response that is atypical.  This stress response was adaptive while the child was in a stressful environment without a consistent caregiver, but is not necessarily adaptive later in life.  This has also been clearly linked to problems later in life for children with international adoption backgrounds, such as problems with higher level cognitive skills (executive functioning), attention skills, and behavioral regulation skills.

Child with very messy faceIn everyday life, I see this issue when I wipe my adopted daughter’s face and she reacts with intense fear and aggression.  Her stress response pathway has been strongly set for an intense reaction early in life.  The theory I just presented would say that I can’t go back in time and re-set the pathway, that it is biologically embedded (epigenetics has taken its course).  However, that doesn’t predetermine that my child will always be aggressive and highly stressed.  Brains are plastic, so it is a matter of determining what can still be changed in the neural pathways and what areas of skills I need to strengthen for my child to help her adapt and cope with how her brain is wired.  By acknowledging and understanding the biological development of a child’s brain, a parent can focus on utilizing parenting and teaching strategies that are tailored to the needs of internationally adopted children given the high risk of developmental problems related to the atypical stress responses.

Up next: A closer look at the stress pathway and where changes might through intervention strategies.

Coming next week- looking at the prefrontal cortex and executive functioning skills.

References

Almas, A. N., Degnan, K. A., Radulescu, A., Nelson, C. A., Zeanah, C. H., & Fox, N. A. (2012).  Effects of early intervention and the moderating effects of brain activity on institutionalized children’s social skills at age 8.  Proceedings of the National Academy of Sciences, 109, 17228-17231.

Beckett, C., Maughan, B., Rutter, M., Castle, J., Colvert, E., Groothues, C., … Sonuga-Barke, E. J. S. (2006).  Do the effects of early deprivation on cognition persist into early adolescence? Finds from the English and Romanian adoptee study.  Child Development, 77,696-711.

Blair, C., Diamond, A. (2008).  Biological processes in prevention and intervention: The promotion of self-regulation as a means of preventing school failure.  Developmental Psychopathology, 20, 899-911.

Keating, D. P. & Hertzman, C. (Eds.). (1999) Developmental health and the wealth of nations.  New York, NY: the Guilford Press.

Gunner, M.R., Morison, S. J., Chisholm, K. & Schuder, M. (2001).  Salivary cortisol levels in children adopted from Romanian orphanages.  Developmental and Psychopathology, 13, 611-628.

Hertzman, C. (2012) Putting the concept of biological embedding in historical perspective.  Proceedings of the National Academy of Sciences, 109, 17160-17167.

Hostinar, C. E., Stellern, S. A., Schaefer, C., Carlson, S. M., & Gunner, M. R. (2012).  Associations between early life adversity and executive functioning in children adopted internationally from orphanages.  Proceedings of the National Academy of Sciences, 109, 17208-17212.

McEwen, B. S. (2012) Brain on stress: How the social environment gets under the skin.  Proceedings of the National Academy of Sciences, 109, 17180-17185.

McEwan, B. S., & Gianaros, P. J. (2010).  Central role of the brain in stress and adaptations: Links to socioeconomic status, health, and disease.  Annals of the New York Academy of Sciences, 1186, 190-222.

Nelson, J. N., Kendall, G. E., & Shields, L. (2014).  Neurological and biological foundations of children’s social and emotional development: An integrated literature review.  The Journal of School Nursing, 30 (4), 240-250.

Shonkoff, J. P. (2012) Leveraging the biology of adversity to address the roots of disparity in health and development.  Proceedings of the National Academy of Sciences, 109, 17302-17307.

ShonKoff, J. P., Boyce, W. T., & McEwan, B. S. (2009).  Neuroscience, molecular biology, and the childhood roots of health disparities: Building a new framework for health promotion and disease prevention.  Journal of American Medical Association, 301(21),2252-2259.

Sokolowski, M. B., Boyce, W. T., & McEwans, B. S. (2013).  Scarred for life? The biology of childhood hardship.  New Science, 217, 28-30.

Paige Hays is an occupational therapist who provides in-home, pediatric occupational therapy services in the south metro area of the Twin Cities, MN. She is a mother of 2 girls, avid DIYer, and a highly skilled and experienced OT. She specializes in working in pediatrics, with diverse expertise ranging from cognition and sensory issues to working with children with neuromuscular disabilities or complex medical needs.