For this lesson, each student will need a piece of firm cardstock or thin cardboard, as well as plasticine, which students will use to create a two-dimensional model of the neuron. Start this lesson by reviewing the basics of a cell, namely the following information:
- The human body is made up of trillions of microscopic parts called cells
- These cells provide structure for the body, take in nutrients from food, convert those nutrients into energy, and carry out specialized functions
- Each cell contains a copy of your DNA, which is genetic information that is passed down from your mother and father and can be thought of as a blueprint for life.
- Within cells there are specialized structures called organelles that perform specific tasks within the cell. Students may be familiar with some of these organelles such as the endoplasmic reticulum (ER), Golgi apparatus, mitochondria, and nucleus.
Next, tell students that neurons are special cells found in the nervous system. Briefly explain that there are two divisions of the nervous system, the central nervous system, which includes the brain and spinal cord, and the peripheral nervous system, which is everything outside of the brain and spinal cord, such as the nerves running from the spinal cord to the limbs.
The nervous system has three main functions:
- Sensory: The sensory function of the nervous system is responsible for collecting information from your internal and external environments.
- Integration: The process of integration involves processing the sensory signals that you collect, and then evaluating, storing, or discarding that information so that it can be used in the future.
- Motor: The motor function of the nervous system is responsible for stimulating other cells, such muscle cells, to initiate a response to the evaluated sensory information.
Let students know that all of these functions are executed in a matter of milliseconds and often occur without conscious awareness. To help students better understand the speed at which the nervous system functions, ask them to think about a time when they stepped on something sharp or touched something hot. Explain that, in this scenario, the sensory information (the pain or heat) is immediately processed and evaluated as “dangerous”. Before students even have the chance to consciously process that information, they’d already be pulling their foot or hand away (motor function of the nervous system).
Now, introduce students to neurons by explaining that neurons are the building blocks of the nervous system and that communication between neurons is what enables us to think, feel, and move. Show students a simple diagram of a neuron and let them know that they are going to be using plasticine to construct their own two-dimensional structures of a neuron while you explain it’s parts. Give every student a piece of cardstock (or thin cardboard) and their choice of plasticine colour.
Start with the cell body. Ask students to make a circle on the cardstock with the plasticine, near the center of the page. Explain that this is the cell body, which is sometimes called the soma. Explain that the cell body contains the nucleus (which is where the genetic information is stored), as well as the other organelles, such as the mitochondria, Golgi apparatus, and endoplasmic reticulum, which are responsible for keeping the cell functioning and alive.
Next, tell students about the dendrites and ask them to use the plasticine to make many short, branched extensions from the cell body to the left side of the page. Explain that dendrites are responsible for receiving information and can be thought of as the antennae of the neuron. Let students know that, at the tip of each dendrite, or dendritic branch, there are thousands of receptors that receive chemical messages, in the form of neurotransmitters. The dendrites mark the “start” of the neuron.
Point out that different neurons will have different sizes of dendrites and different amounts. However, the average neuron has around 5-7 dendrites extending from the cell body, and these dendrites are highly branched. Ask students to describe what the dendrites look like. Then, mention that, because of their extensive branching, the structures that dendrites form are commonly called dendritic trees. Wait for students to be done creating the dendrites before moving on to the axon.
The third and final major part of a neuron is the axon. On the other side of the cell body, ask students to use the plasticine to make a single, long extension from the cell body to the right side of the page, which marks the “end” of the neuron. At the end of the page, students can once again create branches to represent the axon terminals.
Explain that information travels down the axon in the form of an electrical impulse. When the electrical impulse reaches the end of the axon (i.e. the axon terminals), chemical messengers, called neurotransmitters, are released.
Putting it all together, tell students that dendrites receive chemical messages, or neurotransmitters, which are then transformed into electrical signals and sent to the cell body before travelling down the axon. At the end of the axon, the electrical impulse triggers the release of neurotransmitters.
Now, ask students to stand up with their neurons and form a large circle. Students should hold their neurons in front of them so that the axon of one student’s neuron is beside the dendrites of another student’s neuron. Make sure that students are keeping a space between the neurons and inform them that this space is called the synapse. Tell students that neurons are not directly connected to each other but, instead, communicate with each other by sending chemical messengers, or neurotransmitters, across this synapse. At this point, ask students to try explaining how neurons communicate with each other. Choose a student and suggest that the dendrites of their neuron just received a chemical signal from the body.
Use the question, “Now what?” to encourage the student to explain how the chemical signal gets transformed into an electrical signal that travels through the cell body, down the axon, and triggers the release of chemical messengers from the axon terminals. Continue the story by explaining that the chemical messengers that were released at the axon terminals are now floating around in the synapse (the space between the two neurons) until they bind to the receptors on the dendrites of the next neuron. Turn to the next student and ask, “Now what?”.
Encourage students to participate in this kind of storytelling until you believe that they understand the basics of synaptic transmission. Before starting the next game, explain that this type of communication is called synaptic transmission, or sometimes also neurotransmission, because chemical signals are transmitted across the synapse.
Next, play a couple of games of telephone to reinforce how neurons communicate with each other. Before starting the game, ask students to imagine that their words are the chemical messengers, or neurotransmitters, and that these messages are being transmitted from neuron to neuron. Remind students that neurons do not touch each other and that they communicate incredibly quickly. So, students should try to relay the message as quickly AND accurately as possible. Students are only allowed to whisper the phrase to their neighbour once. For the first round, you will pick the phrase and start the game. For subsequent rounds, let students choose the phrase and start the game themselves. Play several rounds (6-8 minutes) and have fun!
After the game of telephone, ask students to return to their seats and conclude this lesson by talking about neuroplasticity. Explain that when neurons communicate with each other, they form a kind of road through the brain. Different behaviours, feelings or thoughts that students have, travel along different roads. Roads that are travelled a lot, are easier to follow and enable faster communication. Ask students to share an example of a behaviour that they do very repetitively.
This example can range from playing a sport, to something as simple as brushing their teeth, or a bad habit. Use a shared example to explain that the information needed to initiate and execute that behaviour travels along a very specific pathway in the brain. Turn to the student whose example you are using and ask them what they think would happen to their ability to perform the behaviour if they no longer practiced it. Students should be able to recognize that they may no longer be able to perform the behaviour as quickly, smoothly, or effectively.
Acknowledge that this is because the road, or pathway, is no longer being travelled. Explain that, to keep communication as fast and efficient as possible, pathways that are not used are weakened, and those that are used are strengthened. At this point, introduce the term neuroplasticity, defining it as the brain's ability to change, remodel and reorganize based on input from repeated behaviours, emotions and thoughts. Ask students to pick up a piece of plasticine and play around with it, suggesting that, similar to how their hands shape the plasticine, their experiences shape the brain.
Finally, watch this brief, two-minute animation about neuroplasticity.
After the video, wrap-up the lesson with a 5-minute discussion using the following prompts:
- Is neuroplasticity inherently good or can it also be bad? Explain your reasoning.
- Your behaviour (i.e. what you do) has the biggest potential to change how your brain is wired. How might knowing this change the way you engage with your life?
- Based on our conversation about neuroplasticity, do you think it’s possible to change your perspective and how you think about things (i.e. mindset)? Why or why not?
- Do you think that this lesson will change the way you approach challenges? If so, how? If not, why not?
- Dr. Lara Boyd, a researcher at the University of British Columbia, suggests that we are able to build the brain we want for ourselves. Do you agree or disagree with this statement? Explain.
Does neuroplasticity involve growing new brain cells or is it just about rewiring connections?
It’s possible for new neurons to be produced over the course of our lives. However, this is a different process called neurogenesis. Neuroplasticity simply involves reorganizing neurons, forming new connections, and strengthening or weakening old connections.
My mom told me that adults can’t learn new things as good as kids can. Does this mean that adult brains are less plastic?
Yes, young brains are more plastic than older brains. One of the facts from our starting activity was that, in your entire lifetime, you have the most neurons when you are born (around 100 billion). During your first three years of life, the number of connections that a single neuron makes with other neurons increases dramatically from 2,500 to 15,000 per neuron (Washington, n.d.). Throughout your adolescence, the number of neurons you have and the number of synapses that each neuron makes is reduced. This is based on the experiences that you have and which pathways are most commonly used. Similar to how muscles atrophy when you don’t use them, synapses and neurons weaken and eventually disappear. By the time you reach late adolescence the number of synaptic connections between neurons is about half of what it was when you were a toddler (Washington, n.d.). Adults CAN learn new things and their brains DO change in response experiences, but because they have fewer connections, and the connections that they do have are more fixed, it can take more time, effort, and energy for their brains to change. You may have heard someone tell your grandparents to stay active, or do things like sudoku, crosswords, or word searches, to prevent memory loss and overall cognitive decline. This is because keeping the brain active and using neural pathways, prevents pathways from weakening.
What factors affect neuroplasticity?
That’s a really good question with a bit of a complex answer! As I’m sure you can imagine, brain plasticity is affected by a number of factors. Today, we focused on how your experiences and learning can affect the way your brain is organized. In addition to experiences and learning, brain plasticity is also affected by internal factors, such as the kind and number of hormones, inflammatory agents, growth factors, and other genetic factors that are in your body. Certain neurological diseases such as Parkinson’s, Schizophrenia, Epilepsy or Strokes can also impact brain plasticity. In addition, eating a healthy diet that provides sufficient vitamins and minerals, and getting enough sleep, are two other critical factors for brain plasticity. Finally, research has also shown that stress can actually change the structure of your brain. I’m sure that there are a myriad of other factors that either facilitate or inhibit brain plasticity, but hopefully this insight is enough for you to understand that we only scratched the surface of neuroplasticity in our class today. Neuroplasticity is a very complex and nuanced process that provides a foundation for human success and survival.
Can I make my brain more plastic?
Yes, there are certain things that you can do to maintain or improve your brain’s plasticity. Some of these things relate to what was discussed in the previous question about factors that affect brain plasticity. For example, it’s important for you to get the right amount of sleep and to eat a balanced diet. Studies have found that optimal brain health depends on having a sufficient amount of vitamins and minerals (ex. Magnesium) and brain plasticity is enhanced by certain nutrients (ex. Omega-3 fatty acids and choline). Leafy greens, nuts, and seeds, are rich in magnesium, while egg yolks, oily fish (ex. salmon) and walnuts, are high in Omega-3 fatty acids and choline.
Physical activity also supports and enhances your brain’s plasticity. Although it's good to engage in intensive exercise 2-3 times a week, you can also integrate physical activity into your day by walking or biking somewhere instead of driving, using the stairs instead of an elevator, or playing with friends after school.
Finally, two of the most effective ways to increase your brain’s plasticity are to mix things up and never stop learning. When you change your routines and/or learn new things, you keep your brain active, use different pathways, and form new connections. The harder the new activity is, the more your brain will grow! Lucky for you, coming to school every day and learning new things is a perfect way to maintain neuroplasticity. Think about each class as an opportunity to create new neural pathways or strengthen existing ones. Show up at school with the intention of building a better brain and try to approach challenges with an open mindset. After all, hard work pays off!