The Human Brain vs. Computers
The human brain is often compared to an extremely advanced computer for skills like storage and information processing; the two are very similar. In fact, in many complicated tasks, the human brain significantly outperforms the most sophisticated supercomputers in the world. But that isn't to say brains and computers are exactly alike. No, if that were true, fully functioning AI would already exist. So besides the obvious, what's the biggest difference between a brain and a computer? What distinguishes these two immensely complicated systems? To answer this question, let's focus on the construction of each system.
We know very well where a computer's power comes from. There are plenty of people who can build these machines from scratch. The brain, on the other hand, is much more intricate and mysterious. Not only does your brain surpass the specs of most supercomputers, it's capable of understanding things that computers haven't even come close to. Yeah, computers are quick and efficient at simple tasks, but take something more complicated like facial recognition. Humans excel at identifying other humans. If you know someone, chances are you can pick out their face in all kinds of different situations. They could be wearing makeup, aged 20 years, or turn their skin blue. You'd still know exactly who they are. A computer would struggle to make those connections. It could tell you the names of every person in your entire city, but it would just as easily get confused by a fake mustache. So why is it that the human brain is capable of so much more?
The Building Blocks of the Human Brain
Like I said, the difference is in the details. To get a better understanding, let's take a closer look at the building blocks of the human brain. I'm talking about the hundred billion nerve cells, or neurons, that influence every thought you have and every decision that you make. Neurons are responsible for transmitting electrochemical signals throughout the brain. To do this, they form intricate webs of neural connections, passing signals from one neuron to the next. Every neuron can make thousands of these connections. That means that each signal can potentially trigger a chain reaction that covers the entire brain in the blink of an eye.
The actual biology of a neural connection is pretty complicated, but to really understand why your brain is so powerful, you should know how these building blocks function. So here's a basic overview. Every neuron is made up of three important parts. The first is the soma. This is the main body of the cell that contains its nucleus. Next are the dendrites. They're a group of feathery filaments located on the outside of the soma. And finally, we have the axon. This is a long, narrow tube that extends from the soma. Even though the axon and soma are connected, the axon can actually be thousands of times longer.
How Neurons Connect and Transmit Signals
So now that you know the players, we can dive deeper into the connections themselves. In order to transmit a signal, two neurons connect by linking the axon of one cell to the dendrites of another. This establishes something called a synapse. Since every neuron can make thousands of connections, neuroscientists estimate that the average human brain contains about 100 trillion synapses.
So what does a synapse actually look like? There's a common misconception that the axon and dendrites physically touch each other when two neurons create a synapse, but there's always a tiny, tiny gap between them. This is known as the synaptic cleft, and it's only about 20 nanometers wide. For reference, that's 20 millionths of a millimeter. But don't let its small size fool you; your synapses contain one of the most important processes in your brain.
The Process of Sending Electrical Signals
How do neurons actually send electrical signals? Well, it's a lot like flipping on a light switch. When it's off, nothing happens; the neuron essentially just sits there. But when the switch is turned on, the neuron springs into action. It's important to remember that each neuron requires a certain amount of stimulation to start working. This is called an activation threshold.
Now, thinking back to our light switch, what happens if you don't push hard enough? Well, you won't actually turn anything on, right? But with enough pressure, you can successfully change the position of the switch. Neurons do the same thing; it only activates when a stimulus crosses that threshold. If it does, an electrical impulse will start at the soma, travel down the axon, and arrive at the synapse.
The Role of Myelin Sheath and Neurotransmitters
Like I said, axons can get pretty long. To make sure the signal moves fast enough, axons are wrapped in a fatty layer called the myelin sheath. This layer insulates the axon and keeps the signal traveling at a steady rate. Once the signal arrives at the synapse, the axon releases a bunch of neurotransmitters. These chemicals cross the synaptic cleft—that tiny gap between the two neurons—and then bind onto a new set of dendrites. Those neurotransmitters are then responsible for stimulating another electrical impulse, which passes through the next neuron. This process repeats over and over again, sending electrochemical signals all over the brain.
Beyond Neurons: The Role of Glial Cells
This sounds pretty complicated, right? Well, when it comes to the human brain, we've just barely scratched the surface. We hardly touched on glia or glial cells. These are non-neural cells that are found in the brain and spinal cord. While they don't process information, glial cells serve a variety of different purposes. One type of glial cell surrounds neurons and holds them in place. Another supplies neurons with nutrients to keep them healthy. A third produces the myelin that wraps around the axon of each neuron and keeps it insulated. Glial cells are often left out of the conversation, but they make up a huge portion of the brain. Scientists estimate that every brain has between 100 billion and 1 trillion glial cells, each one working to support your neurons in one way or another.
| Type of Glial Cell | Function |
|---|---|
| Astrocytes | Surround neurons and hold them in place |
| Microglia | Supply neurons with nutrients |
| Oligodendrocytes | Produce myelin sheath |
Okay, so I think you get the idea: the brain is amazingly complex, but that isn't the only reason why it's so powerful, especially compared to a computer. You see, the brain uses its complexity in a very special way, which awards it a deeper level of subtlety and flexibility. Think back to our light switch analogy. If you push the button hard enough, the light switch will turn on, right? So that means one of your neurons is stimulated enough to start working.
The Brain's Unique Combination of Digital and Analog Signals
Wouldn't that suggest that information transmission in the brain is a binary process? In other words, aren't there only two options: either the neuron is working, or it's not working, right? One or the other. Because that's essentially how computers work. Their signals are digital, which means there are only a finite number of options: on or off, 1 or 0.
Normally, the opposite of a digital signal is called an analog signal. That means the information would be continuous and uninterrupted. But the brain isn't really digital or analog. It's a unique combination of the two. While the individual neurons are either turned on or turned off, the signals themselves can fluctuate. Multiple neurons might fire simultaneously or in a strange pattern to create different kinds of continuous signals. You can imagine how those changes could influence the way the receiving neurons react.
The Brain's Lack of Modularity
Yet another major difference between your brain and a computer lies in its modularity. When a system has modularity, its pieces can be separated into logical, interchangeable sections. For example, if I ask you to show me where your computer's memory comes from, could you? Of course, you could point to the individual parts of the computer that handle the processing and storage of information. And so if your computer runs out of memory, you could remove and replace that small section of the system.
Okay, now what if I asked you to do the same thing for your brain? You might reference the cerebral cortex or the hippocampus, which are both well-known contributors to memory. But there are many more sections of the brain that play an equally important role. I know it is tempting to organize the pieces of the brain according to function. Modularity is usually a helpful way to understand complicated systems. In this case, you might assume the frontal lobe handles one thing, while the temporal lobe handles another. But the pieces of your brain aren't really separate or modular. Everything is tied together.
The Interconnected Nature of the Brain
That means several areas of the brain are activated when you do just about anything. This unique design allows for each part of the brain to influence and strengthen seemingly unrelated processes. Well, take memory and imagination. Don't your creative ideas usually stem from something that stands out in your memory? By activating similar parts of the brain, our cognitive talents are woven together. They strengthen and diversify each other by working in tandem.
Operating Without Software
Finally, the brain distinguishes itself from computers by operating without any kind of software. Without a program to run, a computer can't really do anything; it's just a big hunk of metal and plastic. You build a machine in order to run a certain kind of software. If the brain is like a computer, shouldn't it have software too? This is where the brain-mind distinction usually comes into play. Some scientists claim that your physical brain acts like hardware while your abstract mind is run through your brain like software.
But this model fails to consider how your brain and mind are fundamentally connected. Anytime something happens in your mind, something physically will always reflect that change. In other words, differences in one are consistently tied to differences in the other.
Conclusion: The Power of the Human Brain
Okay, so let's jump back to our original question: how powerful is the human brain? While it's usually equated to a supercomputer, this comparison doesn't really do your brain justice. At its core, the brain might be comprised of a hundred billion light switches, but it uses those switches to blend, adapt, and fluctuate in ways that will continue to baffle scientists for decades to come.
