2-4 Biological Factors that Influence Brain Development
A – Biological Factors
Two biological factors that influence children’s brain development are: the interaction of a child’s environment and their DNA through a mechanism called epigenetics, and the developmental disorder autism. We’ll be talking more about this next.
Many factors influence children’s brain development. As discussed already in this lesson, children’s experiences shape how connections and networks of activity develop in the brain, and this in turn affects how children behave and respond to the world around them.
When children are constantly exposed to stress or neglect, these experiences shape how the brain develops. A common term for this type of stress is called toxic stress.
Although this lesson will not focus on toxic stress, it is important to know that it is a factor that influences children’s brain development. Toxic stress will be a focus of Lesson 13.
Epigenetics
Until recently, scientists thought that very few environmental factors influenced the expression of genes inside our bodies.
But more recent scientific findings indicate that our experiences as children and the environments in which we grow up can and do influence the expression of genes inside our bodies. In addition, these changes can be inherited or passed along from one generation to the next.
Epigenetics is the field of study that looks at mechanisms that regulate the activity of our genes. Epigenetics may provide insights as to why the environments that we grow up in as children may have lasting effects on our brains and bodies.
The upcoming video will explain more about epigenetics. While watching the video, think about main themes.
Video: What is epigenetics? (5:03)
Watch What is epigenetics from TED-Ed on YouTube.
Video Debrief
The important takeaway here is that not only can our earliest experiences affect how connections form in our brains, they can also affect how some of our genes are expressed throughout our lives, which can have long-term impacts on our health and behavior. In essence, some genes can be activated and others inhibited through epigenetic changes.
For example, researchers have found evidence of epigenetic changes to a protein connected to stress responses in the brains of people who were abused as children.
As early childhood educators, when you provide a supportive environment for all children and help children have access to healthy foods, rest, and exercise, you are helping children develop a healthy epigenome.
If you are interested in this topic, one of the readings for this lesson provides more detail:
Institute of Medicine (IOM) and National Research Council (NRC). (2015). The interaction of biology and the environment. In L. Allen & B. B. Kelly (Eds.), Transforming the Workforce for Children Birth Through Age 8: A Unifying Foundation (pp. 57–84). The National Academies Press. [Journal Chapter]
B – Autism Spectrum Disorder
Many of you are likely familiar with the term autism. Autism spectrum disorder (ASD) is a developmental disability based in the brain that begins early in development.
Children and adults with ASD can have significant social, communication, and behavioral challenges. Often, the way people with ASD interact with others, communicate, and behave is different from most other people. Even the way that children and adults with ASD learn can be different.
It is called a spectrum disorder because of the wide variety of experiences, talents, and challenges that people with ASD have. The cognitive abilities of people with ASD can range from gifted to severely challenged. Some people with ASD are unable to communicate verbally, while others have incredible vocabularies.
Almost all people with ASD struggle with social interactions, which can range from mild to severe. And this means that some people with ASD will need a lot of help in their daily lives, while others may not need as much.
The prevalence of ASD has increased in recent years. Doctors and scientist aren’t sure why this is, but it may have to do with better screening and awareness of the disorder.
It is very important to know that vaccines do not cause ASD. There is no scientific or medical evidence to support this false claim.
In 2012, the Centers for Disease Control and Prevention estimated that the prevalence of ASD is about one in 68. This means that during your careers as early childhood educators, you are very likely to work with children with ASD.
ASD and the Brain
ASD is a developmental disorder that is based in the brain. Scientists have found that children and adolescents with ASD have too many synapses in the brain, and they think that this might have to do with a slowing, or incomplete process of pruning connections. These excess connections can greatly impact how the brain functions.
Scientists and doctors are still not sure what exactly causes ASD. They do know that it is has a strong genetic component. For up to 92 percent of identical twins, both have ASD, whereas only 10 percent of fraternal twins do.
While it is clear that ASD has a genetic component, that component is complex. Most cases of ASD cannot be linked to mutations in one gene or even several genetic risk factors.
This makes screening for ASD very challenging. Currently the only way to screen for ASD is through behavioral tests around the second year of life. Before that the signs and symptoms can be hard to see. But scientists think that the brain changes underlying ASD begin very early in life, perhaps even in the womb.
Children typically show ASD symptoms, such as difficulty making eye contact, after the age of 2, but signs of ASD symptoms can present themselves even in the first year of life.
Early Diagnosis and Intervention
A recent brain imaging study found that in the future, doctors may be able to use structural MRI scans to diagnose children at high risk for ASD even earlier.
The study found that by comparing brain scans of infants at high risk for developing ASD at 6 and 12 months to brain scans of infants not at high risk, researchers were able to predict which children would go on to later be diagnosed with ASD at a rate of 81 percent. This means that they were able to correctly predict 8 of the 10 children that would later be diagnosed with ASD.
Diagnosing ASD as early as possible is important. Another recent study found that early intervention can have long-lasting benefits.
In the study, parents of children with ASD between the ages of 2 and 4 received a year of training on how to more effectively interact with children with ASD. Six years after the training, the children in the study had better social communication, fewer repetitive behaviors (common in children with ASD), and fewer of the children were considered to have severe autism, when compared to children whose parents did not get the specialized training.
Video: The World of Autism PSA (1:00)
This video from Autism Speaks describes this complex syndrome. The video is approximately 1 minute long.
Watch The World of Autism PSA from Autism Speaks on YouTube.
Reflection Point
Consider these questions:
- If you have worked with a child with autism, how was that experience? What did you do to support that child?
- Based on what we have learned about brain development and autism, why do you think early intervention is so important?
Early intervention is important because children’s brains are most flexible and open to learning in the earliest years of life. It will be easiest for children to learn new ways to interact socially and learn new behavior patterns as a young child.
C – Developmental Milestones
Only a highly trained specialist can diagnose a child with autism. But as early childhood educators who spend many hours a day with children, carefully watching and taking note of children’s development can help you to identify any areas of concern and possibly recommend that families seek help from a specialist.
If you see behavior that is concerning, or you think that a child may be at risk for developmental delays, including autism, you should talk with parents about your observations and concerns.
Providing a family with tools to monitor their child’s development, such as this one from the Centers for Disease Control and Prevention, can be a way to support that family and child.
References
Autism Speaks. (2015, November 5). The World of Autism | Autism Speaks. [Video]
Bailey, A., Le Couteur, A., Gottesman, I., Bolton, P., Simonoff, E., Yuzda, E., & Rutter, M. (1995). Autism as a strongly genetic disorder: Evidence from a British twin study. Psychological Medicine, 25(1), 63–77.
Christensen, D. L., Baio, J., Van Naarden Braun, K., Bilder, D., Charles, J., Constantino, J., … Yeargin-Allsopp, M. (2016). Prevalence and characteristics of autism spectrum disorder among children aged 8 Years—Autism and Developmental Disabilities Monitoring Network, 11 Sites, United States, 2012. Morbidity and Mortality Weekly Report Surveillance Summaries, 65(3), 1–23. [Report]
Hazlett, H. C., Gu, H., Munsell, B. C., Kim, S. H., Styner, M., Wolff, J. J., … Piven, J. (2017). Early brain development in infants at high risk for autism spectrum disorder. Nature, 542(7641), 348–351.
Kundakovic, M., & Champagne, F. A. (2015). Early-life experience, epigenetics, and the developing brain. Neuropsychopharmacology Reviews, 40, 141–153.
McGowan, P. O., Sasaki, A., D’Alessio, A. C., Dymov, S., Labonté, B., Szyf, M., . . . Meaney, M. J. (2009). Epigenetic regulation of the glucocorticoid receptor in human brain associates with childhood abuse. Nature Neuroscience, 12(3), 342–348.
Pickles, A., Le Couteur, A., Leadbitter, K., Salomone, E., Cole-Fletcher, R., Tobin, H., … Green, J. (2016). Parent-mediated social communication therapy for young children with autism (PACT): Long-term follow-up of a randomised controlled trial. The Lancet, 388(10059), 2501–2509.
Tang, G., Gudsnuk, K., Kuo, S. H., Cotrina, M. L., Rosoklija, G., Sosunov, A., . . . Sulzer, D. (2014). Loss of mTOR-dependent macroautophagy causes autistic-like synaptic pruning deficits. Neuron, 83(5), 1131–1143.
TED-Ed. (2016, June 27). What is epigenetics? – Carlos Guerrero-Bosagna. [Video]
U.S. Department of Health and Human Services, Centers for Disease Control and Prevention. (2017, March 10). Facts about ASD. [Webpage]
U.S. Department of Health and Human Services, Centers for Disease Control and Prevention. (n.d.). Track your child’s developmental milestones. [PDF]
EarlyEdU Alliance (Publisher). (2018). 2-4 Biological factors that influence brain development. In Child Development: Brain Building Course Book. University of Washington. [UW Pressbooks]
