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 2: Brains and Stress

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 2: Brains and Stress

This is part 2/4 in this series of blog posts.

This topic is also available as a full presentation.  For more information, click here.

stressed infantThe brain is how the body interprets, processes, and responds to most stress.  It has specific neural pathways that detect stress, react to stress, and stop reacting to stress.

As noted in the previous section, the current theory is this pathway:  Limbic system processes and stores the stressful events (amygdala –> hippocampus), and then connects to the prefrontal cortex to interpret (hippocampus –> prefrontal cortex).

Research suggests that the basic pathway of the stress is set in early life through biological embedding, but also that the system is highly plastic (changeable) in several ways.  Stressful early life experience may make a brain more vulnerable to life-long problems, but the plasticity in the neural pathway can lead to interventions that might help an individual cope with how his or her brain is wired.  The brain is the mediator of stress through interactions of many complex systems, and research shows that life-long experiences can change how well or poorly it mediates stress.

A closer look at the areas involved:

stressed toddlerSensory information comes into the body through the brain stem to the thalamus (where sensory information is gathered and combined).  This information is then passed to the limbic system: amygdala and hippocampus.

Amygdala- Quickly responds to events with emotional responses.  Chronic stress can cause over-activity of this brain area, resulting in increased anxiety, fear, and aggression.  How sensitive or reactive this system is appears to be biologically embedded early in life.  For example, children who experience high levels of stress early in life appear to have a system that is very sensitive to threats.

Hippocampus- Learns and remembers information, processes emotional aspects of events.  The structure and function of this area appears to be partly determined by genetics (and epigenetics). However, it also is one of the most plastic areas of the brain over the life-span and is greatly impacted by short-term and long-term stress.  Impairments in this area can affect ability to learn and make decisions during new experiences.  Additionally, impairments in this area impact its ability to regulate the HPA axis to terminate the stress response when appropriate.

Prefrontal cortex- Responsible for high-level cognitive functions (problem solving, impulse control, emotional regulation, processing skills).  It provide top-down regulation of stress response through mediation of the hippocampus and amygdala (and the HPA axis).  This area of the brain is also very plastic and can change life-long through learning experiences.

brainimage with stress pathway

A quick example:  You are sitting in your lawn chair supervising children in the sprinkler.  You feel a light, moving touch sensation on your leg.  In an instant, that sensory information goes to the brainstem and the thalamus.  It is then sent to the amygdala, which produces an emotional response of panic, because it got input from the hippocampus which recalled similar sensations being a spider.  You feel an immediate stress response through the SMA and HPA axis pathways (blood pressure goes up, heart rate increases, body tenses, etc).  This info is sent to the prefrontal cortex which allows a person to conscious evaluate and decide, so you look and see a dandelion brushing on your leg.  Your prefrontal cortex sends a message back to the hippocampus to shut down the stress response.  Given a few minutes, your body returns to its normal state.baby crying

All 3 of these areas help to regulate the HPA axis, which promotes allosis (balance in the stress response).  These areas coordinate the brain’s response to stress to be adaptive or maladaptive.  The functioning of these 3 areas and the HPA axis are directly related to the amount of cortisol (stress hormone) in the saliva.  Children who are internationally adopted have higher levels of cortisol in their saliva, implying decreased functioning of this neural pathway.

mother and childProblems can occur at many parts in this system.  The system may over-anticipate stress and be hyper-vigilant. The system may interpret non-threatening events as stressful and dangerous.  The system may not turn on at all when faced with danger.  The system may respond too much or too little based on the amount of stress.  The system may struggle to turn off or terminate a stress response. All of these can lead to dysfunction in everyday life and contribute to life-long problems if not addressed.

The stress response pathway is highly sensitive to human interactions early in life.  The reciprocal relationships with an adult is critical to regulating stress and the absence of a caring adult causes stress and amplifies other negative stressors.  Conversely, the responsive care from an adult can mitigate stressors and be protective to the development of this stress pathway.  Current research is suggesting that interaction with a maternal figure early in life impact the structure and function of the stress pathway through biological embedding and epigenetics.

China Social Welfare Institute

All this scientific background is leading up to an important question: so what can we do to help children who are likely to have had negative early life experiences be successful (such as children who are internationally adopted)?  For myself, I want to know how to help my daughter who reacts with fear when I wipe her face or hands. Research has established there are benefits neurologically from physical activity, social support and engagement, and lessening stress. However, that doesn’t fully explore the impact of the prefrontal cortex and its potential for top-control regulation of the stress responses.

I image the stress pathway from the spinal cord, up to the thalamus, hippocampus, and amygdala to be like the Colorado River in the grand canyon- not much can change its course once it was set.  However, the connection to the prefrontal cortex is more of a meandering river- its course can be change.

Want to know more? Coming next week more information on the prefrontal cortex, executive functioning, and how parents can improve these skills at home.

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.