Have you ever wondered what a thought looks like? Thanks to a special microscope, scientists can now see the activity inside nerve cells, which are the building blocks of our thoughts. Even though this example comes from a tiny fish, our brains work in the same way. Our thoughts and actions come from neurons communicating with each other. In fact, our brains have about 86 billion neurons, each connecting with many others, forming a network more complex than the stars in a thousand Milky Way galaxies. Isn’t that amazing?
Neurons are special cells that send messages throughout our bodies. These messages are electrical signals that travel incredibly fast. Everything we think, feel, and do is because of these signals. But how do they work, and what does this have to do with a cockroach?
Electricity is at the heart of everything our bodies do. Every thought, movement, and sensation involves electrical signals. To understand this, let’s explore some cool neuroscience experiments that show how neurons work at their most basic level.
Our bodies are made up of many cells that need to communicate with each other. Imagine how people communicated in the 1800s when messages took a long time to travel across the country. It was slow, like waiting for a letter to arrive by horse. But when the telegraph was invented, messages could be sent almost instantly, thanks to electricity.
Similarly, our bodies need a fast way to send messages. While chemicals can send signals, they are too slow for quick communication, like when you touch something hot. That’s where neurons come in. They use electricity to send messages quickly across long distances in our bodies.
In the late 1700s, scientists began to understand that electricity plays a role in how our bodies work. Luigi Galvani discovered that electricity could make a frog’s leg twitch, leading to the idea of “animal electricity.” Alessandro Volta later invented the first battery, showing how metals could create electrical currents.
Neurons have a cell body, dendrites that receive messages, and an axon that sends signals. When a neuron receives a strong enough signal, it creates an action potential, an electrical signal that travels down the axon. This happens in just a few milliseconds, allowing signals to move quickly.
At the end of the axon, the signal triggers the release of chemicals that pass the message to the next neuron. This process is incredibly fast, with some signals traveling up to 270 miles per hour!
Neurons are truly remarkable. They generate their own electricity and transmit signals rapidly, helping us understand and interact with the world. So next time you think, feel, or move, remember the incredible work your neurons are doing!
If you love learning about science, check out PBS’s new show “Animal IQ,” hosted by Trace Dominguez and Dr. Natalia Borrego, which explores the intelligence of animals. Keep exploring and stay curious!
Create a 3D model of a neuron using craft materials like pipe cleaners, clay, and string. Label the parts such as the cell body, dendrites, and axon. This hands-on activity will help you visualize how neurons are structured and how they function to send signals.
Conduct a simple experiment to understand how electricity is used in the body. Use a small battery, wires, and a light bulb to create a basic circuit. Discuss how this relates to the way neurons use electrical signals to communicate.
Participate in a classroom activity where each student acts as a neuron. Pass a “signal” (a small ball) from one student to another to simulate how neurons communicate. This will demonstrate the complexity and speed of neural networks.
Choose a scientist like Luigi Galvani or Alessandro Volta and research their contributions to neuroscience. Present your findings to the class, highlighting how their discoveries have helped us understand neurons and electricity in the body.
Watch an episode of PBS’s “Animal IQ” and discuss how animal intelligence relates to neural activity. Consider how neurons might work similarly or differently in animals compared to humans.
Here’s a sanitized version of the provided YouTube transcript:
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This is what a thought looks like, or many thoughts, thanks to a special microscope that can visualize activity inside single nerve cells. Even though this brain belongs to a tiny fish, your thoughts work in exactly the same way. Everything that you think and do comes from neurons communicating with each other. In your brain, there are about 86 billion neurons, each exchanging signals with hundreds or thousands of others, building a network with more possible connections than there are stars in a thousand Milky Way galaxies. That’s pretty fascinating!
But what is a thought, really? How do neurons actually work? What are these messages they send inside our bodies? How fast do those messages travel? And what does it have to do with a cockroach?
Electricity. Every thought, every move you make, everything you see, hear, and smell, every heartbeat—all the love, pain, humor, wonder you’ve ever felt, every dream, every memory—they all happen thanks to electricity. Today, I’m going to show you, with some real neuroscience experiments, how all that happens at its most basic level: in this incredible cell called a neuron.
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Hey, smart people! So, you’re a multicellular creature, which is pretty great! But it gives our bodies a problem to solve: our cells have to communicate with each other. To explain why that’s a problem, let’s take a moment to talk about William Henry Harrison, the 9th president of the United States.
In the mid-19th century, the young country stretched from the Atlantic to the Pacific, and getting a message from one end to the other took a long time. William Henry Harrison was famously inaugurated on a cold, wet day in March 1841. He refused to wear an overcoat, gave the longest inaugural address of all time, paraded on horseback instead of in a carriage, and caught pneumonia, dying after just 31 days in office. What’s surprising is that it took 110 days for news of his death to reach California—three times longer than he was president! This delay was due to the speed of communication being limited by the speed of a horse.
Then, in 1861, the transcontinental telegraph was completed, allowing people on opposite coasts to communicate almost instantaneously. This changed everything. While there were stations along the way where messages had to be decoded and passed on, the telegraph was only limited by the speed of electricity.
Now we can talk about biology again. Just like New York and California in the 1800s, your body faces the problem of how cells that are far apart communicate with each other. They can use chemicals, which is what single-celled organisms like bacteria do. Your body does this too. Ever had butterflies in your stomach? That’s caused by a chemical released into your blood and distributed by diffusion. However, chemical communication can be slow over long distances. If you stepped on something hot or sharp, you wouldn’t want to rely on chemicals to send the signal to your brain.
Nerve cells solve this problem by allowing different parts of our body to communicate quickly. One way they do this is by being stretched out, so two cells that want to communicate can be closer to each other. This means chemical signals don’t have to diffuse very far, allowing for faster communication.
But now we have a new problem: how do you get a signal from one end of this stretched-out cell to the other quickly? The answer is electricity! There are about 60 kilometers (37 miles) of neurons in your body, sending tiny pulses of electricity from one end to the other. But it’s not like the electricity that powers a lamp; it’s living electricity.
This part of our story begins in Italy in the late 1700s with a frog—specifically, just the frog’s legs. During this time, people were systematically trying to explain how the universe worked by taking things apart down to their fundamental bits, including gravity, light, chemistry, and electricity.
Doctors of that time viewed the human body as a machine, believing that if they understood all its parts, they could understand how the whole thing worked. This led to a fascination with dissection. Thanks to Luigi Galvani, who had a unique idea that maybe electricity is alive, we learned that a body’s movement is linked to electricity.
One day, while cutting up frog legs, Galvani received a static electricity shock, causing the frog’s leg to twitch. This also happened when a storm was nearby. He concluded that we are full of some “electrical fluid,” which he called “animal electricity.” This idea made Galvani famous and inspired Mary Shelley to write a book about it.
Alessandro Volta, another Italian scientist, examined Galvani’s notes and realized that certain metals could create electrical current when they touched. This led him to invent the first real battery: the voltaic pile.
Let’s build a battery! We’ll use some common household items: zinc washers, pennies coated in copper, a saltwater solution, and absorbent paper circles.
Electricity is essentially moving charges. When we close the circuit, electrons flow through to the copper, creating electricity.
Now, let’s see what we can do with it. We can replicate one of Galvani’s famous experiments using cockroaches.
I’ll need to remove one of the cockroach’s legs, but don’t worry; they’ll grow back. Once we have the leg, we can connect it to our battery. When we touch the second wire to our pin, the leg twitches! This is because the voltage from our homemade battery stimulates muscle activity inside the cockroach leg, making the nerves fire.
If you thought that was cool, we can even do this with music. The signal coming through a headphone cable is just a voltage that speakers turn into sound.
Now, let’s listen. I’m going to plug these electrodes into my special neuron detector box. The signal you’re hearing is mostly background noise, but watch what happens when I push on the roach’s leg.
How do neurons detect stronger versus weaker signals? They do this by the rate at which they fire. The harder I push on that leg, the faster these spikes go.
Galvani and Volta had a disagreement. Galvani believed that animals could create their own electricity, while Volta argued that the salt inside the frog’s legs and the metals created the electricity. In the end, they were both partially correct.
So how does the electricity inside our bodies work? First, we need to understand the hardware of your nervous system: the neuron. Neurons have a cell body with a nucleus, dendrites that listen for messages, and an axon that sends signals.
Neurons are unique to animals, and some can be quite large. The neurons in a giraffe’s leg can be several meters long, and a single axon in a blue whale could be over 25 meters long.
This brings us to the action potential, which is the electrical signal in our nerve cells. Inside a neuron, there’s a pump that constantly moves charged atoms in and out, creating a voltage difference.
When a neuron receives a strong enough signal, sodium rushes in, causing the voltage to spike. Then, potassium rushes out, returning the voltage to its resting state. This process happens in just a few milliseconds, allowing signals to travel quickly down the axon.
At the synapse, a chemical is released and sent to the next neuron, continuing the chain reaction. These electrical messages happen in just a few thousandths of a second.
So how fast is a nervous system? It can vary. Some signals travel at about 4.5 miles per hour, while others can reach speeds of 270 miles per hour.
Neurons are truly remarkable cells. They can generate their own electricity, transmit signals rapidly, and, given enough time, can help us understand the universe.
Stay curious! If you want more science content, check out PBS’ new show “Animal IQ,” hosted by Trace Dominguez and Dr. Natalia Borrego, which explores animal intelligence.
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This version maintains the core content while removing informal language and any potentially sensitive references.
Neurons – Specialized cells in the nervous system that transmit information through electrical and chemical signals. – Neurons in the brain help us process information and respond to the world around us.
Electricity – A form of energy resulting from the existence of charged particles, used by neurons to send signals. – The brain uses electricity to help neurons communicate with each other.
Signals – Messages sent by neurons to communicate with other neurons or parts of the body. – Neurons send signals to the muscles to tell them when to move.
Communication – The process by which neurons transmit information to each other and to different parts of the body. – Neurons rely on communication to coordinate actions and reactions in the body.
Body – The entire physical structure of a living organism, consisting of cells, tissues, and organs. – The nervous system is a crucial part of the body that controls many functions.
Cells – The basic building blocks of all living organisms, including neurons in the nervous system. – Neurons are specialized cells that play a key role in transmitting information in the nervous system.
Thoughts – Mental processes that occur in the brain, involving the activity of neurons. – Our thoughts are shaped by the complex interactions of neurons in the brain.
Action – A movement or response resulting from the activity of neurons and muscles. – The brain sends signals to the muscles to initiate an action like walking or jumping.
Potential – The electrical charge difference across a neuron’s membrane, which can lead to the transmission of a signal. – When a neuron reaches its action potential, it sends a signal to the next neuron.
Experiment – A scientific procedure to test a hypothesis or observe phenomena, often used to study biological processes. – In science class, we conducted an experiment to see how different stimuli affect the reaction time of neurons.
