What Really Happens to Your Brain During Anesthesia Is Truly Terrifying

Most of us probably know anesthesia as something that puts us to sleep. But what else does it do? Truthfully, we don’t know much. And doctors and scientists don’t, either. Anesthesia is actually one of the most mysterious things about modern day medicine. But here’s what experts think happens.

What exactly is anesthesia?


Anesthesia is almost always used during surgery. | Mahmoud Zayyat/AFP/Getty Images

Anesthesia is the term for insensitivity to pain. It’s commonly used during surgery, typically given either through gas or intravenously. General anesthesia will put you to sleep before surgery. Local anesthesia means you’re likely awake, and it usually only blocks pain in a small area (such as being “numbed” at the dentist prior to having a cavity filled).

Next: Here’s a scary truth about anesthesia. 

The truth is nobody really knows why you lose consciousness

Operation room surgery

There are a lot of unknowns when it comes to anesthesia. | Hin255/iStock/Getty Images

As scary as it sounds, it’s true. Doctors and scientists have never been able to fully figure out why a person loses consciousness when they’re given general anesthesia. There are several theories about what anesthesia does to the brain, but none has been confirmed. It is one of the most common medical procedures in the world, but it remains such a mystery. Interestingly, people don’t dream when they’re under anesthesia. That period of time is just wiped from your memory. People claim to dream, but it’s really just toward the end when the body begins to “wake up.”

Next: This is how anesthesia works. 

Anesthetics bind to proteins in the brain

Immune system

Anesthetics interact with protein receptors. | Ralwel/iStock/Getty Images

It was originally thought that anesthetics bound with lipid membranes of brain cells. However, that theory was disproved in 1984 when scientists found out anesthetics still worked without the presence of lipids. Since then, we’ve learned anesthetics actually interact with protein receptors on the brain — specifically, GABA neurotransmitters. Once activated, GABA receptors can cause neurons in the brain to misfire.

Next: The plot thickened when scientists discovered this. 

Instead of weakening, the brain is more active than ever during anesthesia

MRI Image for Brain

Brain function actually increases under anesthesia. | iStock.com/Highwaystarz-Photography

Anesthesiologist Emery Brown began measuring brain activity through something called an electroencephalogram, which measures the brain’s electrical signals through the scalp. It was initially thought the brain “turned off” during anesthesia. But actually, electrical activity oscillates through the brain — something very different from the brain’s active state. The oscillations appeared to be a result of the anesthetics binding to the GABA receptors, which cause the misfired neurons.

Next: Here’s what experts think happens when you lose consciousness. 

Experts believe anesthesia prevents the brain from communicating with itself

MRI brain scan

Anesthesia affects parts of your brain. | iStock.com/Movus

When neurons “misfire,” they’re not communicating properly with other parts of the brain. Because the GABA receptors interrupt proper firing, the brain can no longer communicate signals throughout itself. With the different parts of the brain unable to interact with each other, the body doesn’t know it’s feeling pain. And it doesn’t know it should be conscious. But it does know it should be doing something, which is why there is still so much brain activity.

Scientists have never been able to fully understand consciousness, but studying anesthesia led Brown to come up with one extremely plausible theory, which he explained in an interview with Tonic: If communication is necessary for consciousness, and the brain can’t communicate, then you can’t be conscious.

Next: Because your brain stops communicating, here’s what it does to your body. 

Anesthesia’s effects on the body

Medical team preparing equipment for surgery

Doctors still don’t know why anesthesia works so well. | iStock.com/Hin255

The effects of anesthesia on different body parts stem from the brain not being able to communicate. The brain can’t send signals to your body telling you it’s feeling pain. It also doesn’t send signals to move your limbs or open your eyes. If the brain can’t communicate, then it loses contact with the body. You’re essentially a doll. Scientists have likened the effects of anesthesia to being in a coma.

However, scientists don’t explain how you continue to breathe even though your brain seems to have lost contact with every other part of your body. The theories that scientists have come up with have not been fully proven.

Next: Anesthesia does have its risks. 

Anesthesia does come with some serious risks

Anesthesia is always serious. | iStock/Getty Images

Overall, general anesthesia is a very safe — though extremely confusing — procedure. However, there are some serious risks. Aspiration pneumonia is one rare risk. This occurs when stomach contents are inadvertently inhaled into your lungs during your operation. It has to do with a relaxed digestive system and can lead to serious breathing complications. So it’s always extremely important to follow your doctor’s eating and drinking restrictions prior to anesthesia.

Other serious complications include a severe allergic reaction or blood pressure complications that can lead to a heart attack or stroke.

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