Big Brain Ideas

Topic Progress:

The Center on the Developing Child at Harvard University have identified five core concepts (big ideas) that summarize what science tells us about brain development.

We are going to talk about two of these core concepts (big ideas).

The first is that “Brains are built over time.”

The second is that “The interaction of genes and early experiences literally shape the developing brain.”

There used to be a debate over which had more influence – nature (determined by genes) or nurture (influenced by the environment. The recent discoveries about how the brain develops have pretty much put this issue to rest. The answer is both. During this session you will learn how nature starts the job of brain development and how environmental experiences refine and shape brain development.

Ann MacDonald compares the newborn’s brain to “early roots in a spring garden” whose growth is influenced by the child’s environment (the human version of sun and rain).

2 MacDonald, A. (2007, November). Brain development in childhood: The DANA guide. Downloaded from http://www.dana.org/news/brainhealth/detail.aspx?id=10054.

Add video: Changing Brains: Imaging/Development

You may watch to watch other videos in this series by using the links on page 4 of your handouts.

When talking about brain development you will hear me use words like “build” or “construct.”

That is because the process of brain development is a lot like building a house.

First, a foundation is laid,

then the rooms (various structures of the brain) are framed in,

and then wiring is laid down (brain cells are wired together)

and then distinctive features are added (that reflect child’s individuality).

This all occurs in a predictable sequence.

Building a strong foundation early increases the likelihood that your child will be more successful – for example in school.

On the other hand, a weak foundation increases the risk of later difficulties.

2Center on the Developing Child at Harvard University (2007). A science-based framework for early childhood policy using evidence to improve outcomes in learning, behavior, and health for vulnerable children. Downloaded from http://www.developingchild.harvard.edu

At birth, the basic foundation has been laid and the structures of the brain are in place, like a house where the rooms have been framed in.

Different parts of the brain have different functions and do different things, just like different rooms in a house have different functions and purposes. For example:

  • Put your hand on the very back of your head. This “room” of the brain is the vision center of the brain and processes all that you see.
  • Put your hands on the side of your head, above your ears. These “rooms” of the brain process what you hear and are involved with other aspects of language (e.g., speaking, reading).

Each “room” of the brain is made up of brain cells called neurons (like a house is made of brick or wood).

At birth, the brain contains 100 billion neurons, most of which are NOT yet connected.

The majority of these neurons have not yet been “wired” together. Imagine a house with all the electrical outlets installed but that have not yet been wired together.

¥Some sources say 200 billion neurons.

¥The purpose of this slide is to help participants understand that different parts of the brain have different functions. It is not necessary that participants learn the names of each brain structure.

2 University of Maine Cooperative Extension. (2001). Brain development: A fact sheet for families and people who work with families. Downloaded from http://www.umext.maine.edu/onlinepubs/PDFpubs/4356.pdf.

One of the things we know about neurons is that neurons in different “rooms” of the brain respond to (are activated by) different types of information (sensory data).

For example, information about what you see (visual information received through the eyes) is sent to the back of your brain to the “seeing room” of the brain where different neurons will respond to different types of visual information such as color and the shape of objects.

So, Likewise, when you hear the word “ball”, the individual sounds that make up the word “ball” (b-a-l) are sent to the “hearing” room where different groups of “hearing” neurons will respond to these three individual sounds.

One of the things we know about neurons is that neurons in different “rooms” of the brain respond to (are activated by) different types of information (sensory data).

For example, information about what you see (visual information received through the eyes) is sent to the back of your brain to the “seeing room” of the brain where different neurons will respond to different types of visual information such as color and the shape of objects.

Do you like to garden?

In some ways, what happens early in the brain is a little like what happens in a flower garden.

In the beginning, genes instruct the brain to make lots and lots of connections between neurons (synapses).

According to researchers at Harvard University, the brain forms 700 new neural connections every second!

This blooming of connections takes place at different times in different areas of the brain.

Think of a garden where different flowers bloom at different times.

The connections referred to here are “synapses” the space between neurons over which the neurons send signals. The process of overproducing synapses is referred to as synaptogenesis.

Genes also determine WHEN this blooming of neural connections (wiring) take places and in what order.

For example, sensory circuits such as those needed for seeing and hearing are the first to develop (bloom),

followed by the circuits need for early language skills such as talking.

Circuits needed for higher cognitive functions such as thinking, judgment and decision-making begin developing (bloom) later and take much longer to be wired.

So the brain goes through a process of creating lots and lots of neural connections.

Now, let’s look at how everyday experiences turn these many connections into something called neural networks.

Insert graph

The primary point is that different parts of the brain develop at different times. Because circuits needed for seeing, hearing and talking develop early, it is very important that children have lots of sensory (hands-on) experiences and that families spend time talking with their children starting at birth.

2Source of graph: Nelson, C. A. (2000). Change and continuity in neurobehavioral development. Infant Behavior and Development, 22, 415-429. Chart © 2009 Center on the Developing Child at Harvard University. www.developingchild.harvard.edu.

When neurons “fire together,” meaning when a set of neurons respond (or are activated) at the same time, the connections between these neurons become wired together forming a specific circuit that is referred to as a neural network.

A neural network is a lot like Sprint’s “circle of friends” – a group of neurons that communicate with (call) each other.

Because these different sets of neurons “fired together” (responded at the same time) when this brain saw this ball, they become wired together, forming a neural network that will be activated every time the brain sees this ball.

The gray dashed line represents the neural network.

The same thing happens with the neurons in the “hearing” room. Because these neurons “fired together” when this brain heard the word “ball,” they became wired together, forming a neural network that will be activated every time this brain hears the word “ball.”

At first, these neural networks will be weak. But the more these neural networks are used (e.g., hear the word “ball”, see a ball), the stronger the connections in the network become (Sprenger, 1999).

This is one of the reasons why children want to do things over and over (e.g., read a favorite book or sing a favorite song). This desire for repetition is driven by the brain’s need to strengthen neural networks.

Eventually, this brain will connect these two networks, forming a larger network that the brain labels “ball.”

As this brain has more and more experiences with balls, it will continue to create and add new neural networks that expand and refine this person’s understanding of the concept of ball.

In reality, this is a very simple example of a very complex process that occurs each child time your child sees, hears, touches something and that information is processed by his/her brain.

These neural networks influence everything from your ability to recognize a letter of the alphabet to your ability to speak a word to your ability to control an emotion such as anger.

When it comes to learning, having lots of neural networks involving multiple rooms in the brain is best.

This means that the more different ways children learn about and experience things and the more senses that are involved, the better.

Let’s take the example of learning about shapes.

When a child has opportunities to play with blocks of different shapes, read books about shapes, create art using different shapes, play with shape toys and puzzles, and to talk about shapes, the brain makes multiple connections between neurons in different rooms of the brain. This makes it easier for the brain to access information about shapes when needed.

So, as a parent, you don’t need to use a worksheet or flash cards to teach your child about shapes. You can take advantage of everyday experiences to talk about and help children learn about shapes – such as talking about how plates are circles, cereal boxes are rectangles, etc.

Earlier, I explained that the brain goes through a period where it “blooms” lots and lots of connections between neurons.

So, imagine that now you have this garden (brain) that has too many flowers (neural networks) – the garden is too crowded.

A good gardener knows that pruning back some of the flowers will lead to a better, healthier garden

Earlier, I explained that the brain goes through a period where it “blooms” lots and lots of connections between neurons.

So, imagine that now you have this garden (brain) that has too many flowers (neural networks) – the garden is too crowded.

A good gardener knows that pruning back some of the flowers will lead to a better, healthier garden

A young infant (e.g., 3 months old) has the ability to “hear” (or distinguish between) all the various sounds made by all the various languages in the world (phonemes).

During the first year, the child’s brain will strengthen the neural connections for the language sounds that the child hears in his/her environment.

And, as the brain organizes itself to become more efficient, it will “prune” the connections for the remaining language sounds that the infant never heard.

Let me give you a practical example.

Ask Yourself: Do you have a child or know a child that had frequent ear infections between when they were born and their first birthday?

Ask Yourself: How many of these children ended up having language or speech delays?

Ear infections muffle or distort the sounds children hear. This influences how the hearing part of the brain is wired. Wiring for some sounds may be lost or wired improperly because some of the neurons in the hearing part of the brain were not used.

That is why speech therapy may be required to help rewire some of the neural connections so that the child hears language properly.

During early childhood, the brain retains the ability to relearn sounds it has discarded, so young children typically learn new languages easily and without an accent. After about age 10, however, plasticity (brain’s ability to change) for this function decreases. This is why most adults find it difficult to learn a foreign language and why, if they did not begin to learn a language til adolescence or adulthood, they will probably always speak the foreign language with an accent.

2Hawley, T. Starting smart: How early experiences affect brain development. Retrieved on Jan 15, 2010 from http://www.zerotothree.org/site/DocServer/startingsmart.pdf?docID=2422.

 This video, Changing Brains: Hearing (8 minutes), explains how hearing develops, the impact of persistent ear infections on the development of hearing and the role families can play in fostering good hearing. This video is one of 12 excellent videos in the Changing Brains series developed by the University of Oregon Brain Lab (www.changingbrains.org). After watching the video, point out the website on page 4 of the participants’ handout and encourage participants to watch other videos in this series.

This video, Changing Brains: Language (9 minutes), explains how language develops and the role families can play in fostering good language skills.

So basically, brain development is a process that involves the “wiring” up of connections between neurons.

1.Initially, the brain “blooms” lots and lots of connections between neurons.

2.Experiences determine which of these connections are strengthened and become wired together as neural networks. The more your child’s brain uses a specific neural network, the stronger the connections in that network become (Sprenger, 1999). (Neurons that “fire together” are wired together)

3.Other connections that are not used are pruned away to make the brain more efficient. (“Use it or lose it” principle)

2Sprenger, M. (1999). Learning & memory: The brain in action. Alexandria, VA: ASCD.

You may be wondering, “What is the point of all of this? What is the big deal about understanding how the brain is wired into neural networks?”

The point is that you have a neural network for everything you know, do and feel.

AND…it is the experiences that you had that created these neural networks that become what we call knowledge.

In a book The Art of Changing the Brain, Zull (2002) explains that “There is a neural network for everything we know…It seems that every fact we understand, and every action we take has the form of a network of neurons in our brain. Complex experiences or ideas consist of extensive networks…Any change in knowledge must come from change in neural networks (pp., 98-99).”

2Zull, J. (2002). The art of changing the brain. Sterling, VA: Stylus Publishing, LLC.

2Zull, J. (2004, September). The art of changing the brain. Educational Leadership, 62(1), 68-72.

As a parent, grandparent, foster parent or teacher, you will determine the kinds of everyday experiences and interactions that will build the neural networks that will become the foundation for everything that your child will know, do and feel.

This is why early experiences during your child’s first five years are so important.

Early experiences literally shape the brain, building the foundation upon which everything your child ever learns will be based.

The experiences and interactions your child has with people and objects in his/her environment will determine which connections are used and which are not and therefore, which connections will be kept and which will be pruned.

So, although genes are responsible for creating the brain’s structures and for producing lots of neural connections, it is the child’s specific experiences and interactions that will fine-tune these connections and shape the way the brain develops. It is your child’s experiences that determines which of those neural connections are strengthened and formed into the neural networks that we talked about earlier.

Now here is the good news. You don’t have to run out and buy specific toys or do specific things to “make your child smarter.”

Many of the things you already do everyday contribute to your child’s brain development.

Scientists have found that normal everyday experiences and loving, responsive adult/child interactions seem to provide the exact kinds of experiences a child’s developing brain needs.

When you provide your child with age-appropriate materials to play with and when you spend time with your child – playing, reading, singing – your child gets the kinds of experiences needed to develop his/her brain and prepare him/her to succeed in school.

However…these are the very things that get lost in the shuffle in today’s busy families.