If We’re Going to Talk About Brainwaves, We Should Know What They Are
A lay explanation of what brainwaves actually are.
Brainwaves come up in conversation a lot, especially when you’re talking about mindfulness, creativity, falling asleep, and other processes we’re trying to understand. But do you know what a brainwave actually is? It’s kind of surprising.
Most of us have heard about at least some of these major brainwave categories (there are sub-categories, too):
The human brain contains nerve cells called neurons that produce tiny electrical charges, some of which are sent to other neurons that produce and send their own, and so on. There are billions of neurons firing off at any given time.
With so many charges firing off, you’d think all of this electricity would add up, and it does. These being tiny amounts of electricity, though, the electrical output an electrode picks up is only between 4 and 200 millionths of a volt on the scalp. (It would be 1-2 mV directly on the surface of the brain.)
If all of the neurons fired at once, the brain would output about 0.085 watts, about what it takes to light a light bulb. It would take about 68 hours to charge an iPhone 5C.
The EEG creates a graph that charts the amount of power the electrodes receive from the brain at a given moment.
The chart’s vertical axis shows the strength, or amplitude, of the current, while the horizontal time axis shows how it fluctuates over time. A brain’s output fluctuates up and down between its highest and lowest amplitude in a cyclic manner, producing the wavy patterns the EEG draws.
Can you guess what that wavy pattern is? Yep. That pattern itself is a brainwave. It doesn’t show a brainwave in the brain—there is no brain wave in the brain itself. A brainwave is just a graph of the fluctuating electrical output of a brain.
A brainwave’s frequency refers to how frequently the wave in the graph cycles between its highest and lowest amplitudes. If it does it six times per second, it’s a theta brainwave; if it does it 30 times, it’s a beta brainwave.Researchers have noted that certain brainwave frequencies are seen when subjects are in certain mental states. They don’t cause these states, of course—how could they, they’re just the visual artifacts in a graph on an EEG machine?
We don’t mean to suggest brainwaves aren’t important. Doctors have seen that some brain events, like epileptic seizures, are accompanied by certain types of brainwaves, so the EEG is an important diagnostic tool for confirming what’s been happening in a patient’s brain. Even more, it’s a consistent and reliable way of observing what this mysterious and powerful organ is up to.
The Russian-built FEDOR was launched on a mission to help ISS astronauts.
Most people think human extinction would be bad. These people aren't philosophers.
- A new opinion piece in The New York Times argues that humanity is so horrible to other forms of life that our extinction wouldn't be all that bad, morally speaking.
- The author, Dr. Todd May, is a philosopher who is known for advising the writers of The Good Place.
- The idea of human extinction is a big one, with lots of disagreement on its moral value.
Picking up where we left off a year ago, a conversation about the homeostatic imperative as it plays out in everything from bacteria to pharmaceutical companies—and how the marvelous apparatus of the human mind also gets us into all kinds of trouble.
- "Prior to nervous systems: no mind, no consciousness, no intention in the full sense of the term. After nervous systems, gradually we ascend to this possibility of having to this possibility of having minds, having consciousness, and having reasoning that allows us to arrive at some of these very interesting decisions."
- "We are fragile culturally and socially…but life is fragile to begin with. All that it takes is a little bit of bad luck in the management of those supports, and you're cooked…you can actually be cooked—with global warming!"