What Does Anesthesia Do to Your Brain?


I don’t mean to alarm anyone, but we don’t
really know exactly how general anesthesia works. We do know THAT it works, and that it’s
relatively safe. But scientists are still trying to figure out how all these different
chemicals switch out the lights in your brain. Anesthesia is a state where you’re insensitive
to pain, and doctors use it so that when they need to get to your heart or kidneys or whatever,
they can turn something invasive and traumatic into a peaceful nap. General anesthesia is the kind that knocks
you out completely — as opposed to local anesthesia, which just numbs a part of your
body for a while, or twilight sedation, where you’re technically conscious but won’t
remember anything that happened. Usually, general anesthesia involves a combination
of two drugs — the first knocks you out fast, and the other one keeps you that way. The
anesthesiologist can fine-tune the dosage of the second drug to make sure you don’t
wake up too early, or go too far under. So we know that anesthetics knock you unconscious,
and we know that they keep you from feeling pain, responding to your environment and — almost
always — from remembering what happened. Which is a huge plus, because feeling — and
remembering — being sliced up and stitched back together would not be pleasant. But anesthesia’s not the same as going to
sleep. Some parts of the brain are still active,
but unlike when you’re fully conscious, those active parts don’t really communicate
with each other. The brain patterns of someone under anesthesia
don’t look like sleep, either. There’s no rapid eye movement or dreaming under anesthesia. Anesthesia brainwaves actually look a lot
like the brainwaves of a coma patient… which makes sense, because anesthesia is a lot like
a coma. It’s just reversible under the doctor’s control. The weird thing is, this same anesthetic state
can be brought on by a whole bunch of different chemicals–from the noble gas xenon, to big
molecules made up of rings of carbon. Since all these different anesthetics do similar
things, scientists figured they must have something in common. And the most obvious
one was that they almost all dissolve in oil… oils like the insides of your cell membranes. For decades, researchers thought that anesthetics
could dissolve in the membranes of your brain cells and disrupt them somehow. But some compounds that are similar to anesthetics
and very oil-soluble don’t numb pain. And some anesthetics aren’t very oil-soluble
at all. Instead, these days scientists think it has
more to do with proteins, which have oily patches too. So anesthetics probably bond
to proteins in your brain. But it’s hard to study drugs that bond in
an oily environment. Anesthetics bond very weakly to the proteins
they act on, and it’s hard to get them to stick in place for long enough to know exactly
where they’re stuck. The best understood anesthetic is also one
of the most popular: propofol. Propofol binds the receptor for a chemical
messenger called GABA, which is involved in controlling sleep and alertness, among other
things. Propofol helps activate the brain’s receptors
for GABA — and researchers think it’s especially active in the part of the brain that handles
sleep. What we don’t know is exactly how that part
of the brain controls consciousness, and how propofol switches it off, and then back on
again as soon as it goes away. But, since studies have found that there’s
also a bunch of other anesthetics that also bind to the GABA receptor, researchers think
they’re on the right track. There is one really strange thing we do know:
Redheads need more anesthetic. Doctors have been reporting cases of this
for a while, and at least one small study showed that redheads need 19% more anesthetic
than people with dark hair. According to the authors of the study, the
gene that produces red hair color seems to be related to resistance to anesthetic, especially
since it’s also been linked to pain sensitivity. So we don’t really know how general anesthesia
works, but it’s a good thing that it does. And as we study it, we’re going to be learning
more about how the brain is put together — and maybe a little more about gingers. Thanks for watching this episode of SciShow,
which was brought to you by Crash Course Anatomy and Physiology: your opportunity to learn
more about how your body works and do well in your A&P class…or just know more stuff
about the world. You can find that at youtube.com/crashcourse where I host, and some other people host,
really great courses that you might not know about. I’m just guessing. Maybe you don’t
know about that thing, but it’s really great! Check it out. If you want to see more of this
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100 thoughts on “What Does Anesthesia Do to Your Brain?”

  1. You know how you temporarily not exist when you are under anesthetic? You can't form memories, you cant feel anything, see anything, sense anything; your consciousness literally pops out of existence and you aren't even aware of it? What if being under anesthetic is what death is like? No feelings, no thoughts, no consciousness, you just cease to be. As someone who has been under anesthetic twice it kinda messes with my head thinking about it, how my consciousness popped out of existence and suddenly I am in a hospital room as if I just blinked.

    It is scary but if death is really like that then I guess I have no reason to fear it, if it is anything like anesthesia where you simply don't exist anymore then it's peace of mind knowing that it isn't scary on the other side, you cant comprehend nothingness thus you can't be afraid of it.

  2. This is interesting to watch, especially since I had to get all four of my wisdom teeth out 10 days ago, and I actually got general anesthesia

  3. I had to get my wisdom teeth removed and went through general anesthetic and it took about 30 seconds until I was out and felt like I woke up a second later when in reality it was 2 hours

  4. Most people say that they feel like its only been like a second since they've been out when waking up? I had surgery on my spine 2 times, and they both lasted 4-5 hours, and while it certainly didn't feel like that, I could realise that time had passed… somehow. Can't explain it, does anyone understand what I'm trying to say?

  5. omg dued i had anatheasia twise and you do remeber them giving it to you but everything else is just like nop you cant remeber btw i had surgery to get gromets can you do a video about gromets it will realy help me understand what they do

  6. It’s almost more than a little unsettling that modern medicine doesn’t understand how anesthesia works. I guess I thought that it did, since it is used every day across the globe. It is also a little unsettling that our brains react to these chemicals and medications like we are in a coma. Not sleeping, not awake. But somewhere in between.

    The fact that there are numerous chemicals/drugs/whatever it is that make our brains react this way is curious to me, because if there are so many it seems like more would be known about them than there is now.

    I guess in the scheme of things, though, discovering how anesthesia works is not at the top of scientists list. Merely the fact that it does work suffices.

  7. I was in surgery for 6 hours before and it felt like two seconds. it's a weird experience. you can't explain it. you have to experience it to understand

  8. I think you need to learn the correct pronunciation for Anaesthetic, its "Anaesthhhetic" with a 'th' sound no hard 'tee". Definitely not "AnaesTetic"!!!!
    Silly Americans

  9. anesthesia is not good for us. After i had a 40 minute operation( this is not so long), i have worse koncentration and im only 17 years old. I dont know what happend, but I know that its not good for brain and im not the only. Science, please help and answer why!

  10. Gawd… I'm about to get my wisdom teeth pulled and I'm going be on anesthesia and I'm terrified of spilling my dirty secrets to my parents

  11. Being put under anesthesia is the closest feeling to death you can get

    When under anesthesia all brain activity stops except functions like heart kidneys etc, there is no "mind" left, there is no feeling of time passing like when you're dreaming, no feeling, nothing

  12. I was fearing twilight sedation for a colonoscopy. From what I read on google people are awake the whole time. Now that I’ve had it done I can honestly say i can’t remember a single thing or feeling. I was knocked out. I did explain to the anesthetist before hand that I was scared beyond belief and that I didn’t want to be awake. He said it was his job to keep an eye on me, if I was waking up he’d just pump me with more drugs. It was such an easy procedure for something that sounds so horrible.

  13. All you have to say is that anesthesia slow down or stops you nerve cells functions so you would not feel pain and what is going on around you. Alcohol and drugs does the same thing but they are in much lower dosage. That is you should not get drunk because your brain is covered with intoxications.

  14. My first experience with anesthesia felt like dying in peace. It was so weird. It felt like I had no consciousness and it felt so good. The operation lasted about 1hr and 30 minutes, yet it felt like I had been asleep for 1 minute… while simultaneously it felt like I would never wake up. Nonetheless I still want to go back to that state lol

  15. Could someone slip into a coma from general anesthesia? I have to get my wisdom teeth pulled in two days and my anxiety has me asking all these questions.

  16. It's never a peaceful sleep. More like a REALLY BAD HANG OVER

    Side note…mad how ya DON'T dream wen under. Not ever.!! (Been under 4 about 46hrs[5-6 different opps] so I FEEL i am the perfect person 2 speak on this. Maybe.?)

    EXPERTS BELOW….

  17. Must you make all those over-animated hand/arm movements? Are you Italian or something? Perhaps a quick whiff of gas might calm you down? Got irritated and turned off at 3:50

  18. I was pumped full of that stuff so my ingrown toenails could be fixed. And what I found scariest, is that I can't remember anything which had occurred on that day.

  19. I was terrified last year for my first surgery after I broke my elbow, had my pins removed yesterday and I wasn’t as anxious as I was the first time. One minute your awake, then you go a little dizzy as you feel the cold liquid go up your arm and the next minute you wake up surrounded by nurses. You have no recollection of time what so ever.

  20. My dad has this thing we he seems to have a high resistance to anathesia, it takes more anathestics to put him under and he wakes up hours earlier than others

  21. I’ve had all the sedition’s. Today I had propofol again. It’s my favorite. I like to see how long I can fight it but I can’t get beyond the few seconds when your face feels flush. I’m having it again in April so I’m going to try meditation. If anything it helps distract me from my pending surgery

  22. When everytime when I have open heart surgery when they put me in anesthesia I feel nothing I just ack like myself people trying to remake that one kid who making a story bout Dubai

  23. I would say that anesthesia is basically identical to death, except it’s reversible. A death simulator. So if you wanna know what happens after death, it’s a great way to find out.

  24. I just have a question. I can’t find the answer anywhere… when I was under general anesthesia, I was coughing …then apparently I started shaking when I was under. My mom said it was a scary seizure, she was there in the room until that point lol. Why does this happen? Is this normal?

  25. The one time I went under general anesthesia it was a great experience.
    The doctors tell you to count down and take deep breaths and for the last breath I took before being knocked out I started to get the feeling that my face was burning up, it wasn't really painful though.
    And a split second later I wake up in the after surgery room and stay awake just long enough until a nice lady told me that everything went well and then I woke up in my hospital room.

  26. Umm I was once under general anesthesia and I had a strange dream and knew I was under surgery. However I didn’t feel any pain.

  27. I love when I’m almost asleep but I’m fading in a out of sleeping and awake. It’s like an out of body experience because it doesn’t feel like it’s you.

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