Brain Development

Table of Contents

1. Early brain development
   1. Architecture of the brain
   2. Neural pathways
   3. Experience-based brain development
      1. Genes and environment
      2. Early brain development: A foundation for life
2. Research related to early brain development
   1. Lessons on maternal care from animal studies
   2. Autism and the social brain
   3. Stress and the developing brain
   4. Memory
3. Implications for best practices based on recent findings about experience-based brain development
   1. Value the quality of everyday experiences
   2. Observe children's behaviour
   3. Use reliable information
4. References

 

1.2. Neural pathways

Making Connections

The connections between neurons are called synapses. Connected neurons form millions of neural pathways in our brain and in the central nervous system that is the brain’s communication system throughout the body.

Each neuron has a nucleus, axons and dendrites.

Neurotransmitters are chemicals in the ends of the axons that carry messages across the synapse from one neuron to the next.

But building connections is not all that happens in the first months and years of life. Neurons, connections and even whole neural pathways are discarded and others are strengthened. The brain increases its efficiency by eliminating little used pathways and reinforcing useful ones.

The process of connecting and refining is known as brain “wiring” or “sculpting” and it continues through childhood and adolescence. Neurons are the basic building blocks of the brain. Based on genes and experience, neurons are connected to form networks or neural pathways.  Networks that are underdeveloped are pruned.

The brain’s architecture and the child’s skills are built from the bottom up. Each stage of brain development rests on another. Neural circuits that process basic information, such as sights, sounds and touch, or govern basic functions, such as breathing, are wired before those that process more complex information. Neural pathways for reading or solving abstract problems build on earlier pathways for vision, hearing, or touch, just as children’s skills build on earlier skills.

The slide below illustrates how the formation of synapses for different neural pathways takes place at different times.

• The pathways for hearing, seeing, feeling, smelling, tasting and movement are under construction before birth and are mostly completed by age four years. Sensory neural pathways set most of the brain’s ability to interpret the signals and pathways that govern or control intellectual, emotional, psychological, and physical responses to stimuli.
• Neural pathways that are key to the capacity to cope -  to respond and adapt to daily experiences, interactions and challenges - begin to form before birth. Construction is very active in the early months and years of life. Visual and auditory areas of the cortex and limbic system pathways precede receptive language systems, which in turn precede speech.
• The neural pathways responsible for language and thinking begin early and construction continues into middle childhood and adolescence. These neural pathways build on the sensory and coping neural pathways. Later developments in the prefrontal cortex support higher cognitive functions and build on the foundation of the earlier neural pathways.

Early brain development is for the long term. Neural pathways may adapt and change over time, but their basic early structure stays with us for life.  Synapse formation is most active during the early years. The brain’s early neural pathways are platforms that support later connections between neurons.

A sensitive period is a time that is optimal for behaviour to emerge and the brain is particularly primed to respond to environmental stimulation.

In the following clip, Bryan Kolb discusses brain development in the context of sensitive periods.

View >>  (2:08)

Brain plasticity is the brain’s capacity to change in response to experiences. We have known for a long time that physical experiences such as nutrition are important for early brain development but now understand that social interactions are also profoundly important. Experiences such as joy, love, fear and loneliness actually affect brain synapses. While brain plasticity is greatest during the prenatal and early childhood period, brain plasticity remains throughout childhood, adolescence, and even into adulthood and later life.

Find out more about brain plasticity from Bryan Kolb:

View >>  (2:12) not available in this preview

Having a child is a life-altering experience as all new parents learn. The following article (McIlroy, 2004) explains that babies aren’t the only ones whose brains are being wired in the first few months of life:

Read >> The Moms Must be Crazy not available in this preview