Neuroscience research has shown us that early childhood is a time of tremendous brain development. The young brain literally changes shape and size in response to everything encountered in the early years. New environment, life experiences, caretakers and relationships can all affect the way children’s brains become wired.
Find out how to help your child’s brain develop optimally.
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Baby Brain Development
A baby is born with roughly 100 billion neurons1, almost all the neurons the brain will ever have2.
Although a newborn has about the same number of neurons as an adult, it has only 25% of its adult brain volume.
That’s because infant’s neurons are connected by only some 50 trillion connections, called synapses, whereas a grownup has about 500 trillion of them3.
This network of synaptic connections will ultimately determine how a child thinks and acts.
What Is Synaptic Pruning
The network of synapses grows rapidly during the first year and continues to do so during toddlerhood.
By age 3, the synaptic connections have grown to 1000 trillion.
But not all of the synapses will remain as the child grows.
Life experience will activate certain neurons, create new connections among them and strengthen existing connections, called myelination.
Unused connections will eventually be eliminated. This is called synaptic pruning4.
Synaptic pruning is the process in which unused neurons and connections are eliminated to increase efficiency in neuronal transmissions.
Building massive connections, creating and strengthening them through life experiences and pruning unused ones is a remarkable characteristic of human brains.
This experience-based plasticity allows babies to adapt flexibly to any environment they’re born into without the constraint of too many hardwired connections5.
The Early Years – Use It Or Lose It
The benefits of creating a brain this way are enormous, but so are the costs and the risks.
First, children require a lot of care, i.e. life experiences, before they can be independent.
Second, what parents do or don’t do during the formative years can have a profound impact on the child’s life.
Here’s a synaptic pruning example. Let’s say a parent consistently shows a toddler love and care, then the “love-and-care connections” will develop or strengthen over time. But if the parent constantly punishes or is harsh to the child, then the “punitive-and-harsh connections” will be stronger instead. And because the love-and-care experience is missing, those corresponding brain cells will wither and eventually be removed from the child’s brain network. As a result, the child grows up lacking the love-and-care understanding that is essential to create healthy, meaningful relationships in his future life6.
Early life is a period of unique sensitivity during which experience bestows enduring effects.
Although this experience-based brain plasticity is present throughout one’s life, a child’s brain is a lot more plastic than a mature one.
Brain cell pruning also occurs most rapidly during a child’s preschool years.
The density of these connections during adulthood will reduce to half of that in a toddler at age two.
This is why nurturing and positive parenting are so important.
Things can go seriously wrong for children deprived of basic social and emotional nurturing.
Critical / Sensitive Periods
Within the early years, there are also windows of time when different regions of the brain become relatively more sensitive to life experiences.
These periods of time are called critical periods or sensitive periods.
During a critical period, synaptic connections in those brain regions are more plastic and malleable. Connections are formed or strengthened given the appropriate experiences. After the critical period has passed, the synapses become stabilized and a lot less plastic.
For example, a young child can learn a new language and attain proficiency more easily before puberty. So the sensitive period for language mastery is from birth to before puberty.
Critical or sensitive period is another reason why early life experiences matter so much.
Related: Critical Period In Brain Development
Nature vs Nurture In Child Development
Besides influencing how the network of brain cells is formed, early life experience potentially has another significant impact on a child’s life.
A large amount of scientific evidence indicates that life experience can affect gene expression — how information in a gene is used (epigenetics) — in some cases by slowing or shutting the genes off, and in others by increasing their output7.
This is why identical twins are not carbon copies of each other.
Although their genes (DNA code) are identical, their epigenetic markers are different from birth and continue to diverge as they interact with the environment in distinctive ways.
Even more important, these epigenetic changes can be permanent and passed down from generation to generation.
In the age-old nature-versus-nurture debate, epigenetics offers a surprising middle ground.
Genes are profoundly important, but so are environmental factors.
When does a fetus develop a brain
Neuron production in the fetus begins in week 3 post-conception during the embryonic period.
As neurons are produced, they migrate to different brain areas to form rudimentary structures of the brain, central nervous system, and peripheral nervous system.
This is a period of rapid brain growth to create cortical and subcortical structures.
When does the brain stop developing
On average, the brain is fully developed by age 25. Although an individual’s brain growth trajectory can vary slightly, most people’s brain development is complete in their mid-20s.
However, it doesn’t mean the brain stops changing.
The interconnections in our brains keep changing throughout our lives, but as we age, they do so at a much slower rate.
The Importance Of Brain Development In Early Childhood
Neuroplasticity and epigenesis are two major cornerstones in understanding child brain development.
While we don’t need to be perfect parents (and who can be?), good enough parenting can do a child tremendous good.
In particular, among the different parenting styles, authoritative parenting is the best parenting style associated with the best outcome while other types of parenting styles can lead to a devastating consequence.
Early childhood education is also important to a child’s cognitive growth. Attending a quality preschool has been shown to benefit kids’ development in the long term.
- 1.Aoki C, Siekevitz P. Plasticity in brain development. Sci Am. 1988;259(6):56-64. https://www.ncbi.nlm.nih.gov/pubmed/2849807.
- 2.Graham J. Children and Brain Development: What We Know About How Children Learn. Cooperative Extension Publications. https://extension.umaine.edu/publications/4356e/.
- 3.Gauvain M, Cole M. Readings on the Development of Children. 5th ed. Worth Publishers; 2008.
- 4.Tau GZ, Peterson BS. Normal Development of Brain Circuits. Neuropsychopharmacol. September 2009:147-168. doi:10.1038/npp.2009.115
- 5.Huttenlocher P. Synapse elimination and plasticity in developing human cerebral cortex. Am J Ment Defic. 1984;88(5):488-496. https://www.ncbi.nlm.nih.gov/pubmed/6731486.
- 6.Wright MO, Crawford E, Del Castillo D. Childhood emotional maltreatment and later psychological distress among college students: The mediating role of maladaptive schemas. Child Abuse & Neglect. January 2009:59-68. doi:10.1016/j.chiabu.2008.12.007
- 7.Stiles J, Jernigan TL. The Basics of Brain Development. Neuropsychol Rev. November 2010:327-348. doi:10.1007/s11065-010-9148-4