
Propofol-induced deep sedation reduces emotional episodic memory reconsolidation - danieltillett
https://advances.sciencemag.org/content/5/3/eaav3801
======
lordnacho
I wondered about this at one point. I'd been under full propofol sleep a
couple of times due to knee operations, and the experience was quite
interesting.

You fall out of consciousness insanely fast. One moment you're talking to the
anaesthetist about your name, what you're there for. You feel a cool sensation
where the needle is. Before it's grown to your whole arm, you've vanished. I
mean you're not dreaming, you're gone.

The only way you know you were gone is that there's no sensation of time. When
you sleep, you feel like there's time. Under propofol I felt like my arm was
cold, then I was groggy and waking up. In one action.

Maybe it's like dying, I don't know. But there's definitely this "system was
rebooted" sensation as you come back to consciousness.

~~~
fnordsensei
I've only been under once, and it was the strangest thing: I had an out-of-
body experience. When I woke up, it was like I had two sets of "memories" (for
lack of a better word): one was nothing (like you describe), and the other was
the OBE. I presume that I wouldn't have been able to notice the span "nothing"
(because it didn't contain any time or space references as I can tell) at all
if there wasn't a sort of parallel overlay of the OBE.

By the way, this hasn't led to me drawing any particular conclusions about the
nature of reality or consciousness. I didn't find it useful to hold a
particular set of beliefs about these things before the event, and that didn't
change afterwards. If anything, it just presents more questions.

~~~
rhizome
I'm no neurologist, but I can picture a brain retconning the OBE as a reaction
to the knowledge that time had passed when you didn't perceive that it did.

[https://en.wikipedia.org/wiki/Retroactive_continuity](https://en.wikipedia.org/wiki/Retroactive_continuity)

~~~
fnordsensei
Yep, very plausible. Also, some parts of the brain would still be active, I
wasn't brain-dead after all.

The OBE itself had some dream-like qualities, though one thing I did notice
was that the "resolution" was superb, unlike my normal dreams. We're talking
next-gen graphics. The closest thing I can compare it to is as if the entire
field of vision was center of focus.

~~~
nickpsecurity
If you study lucid dreaming, more of your dreams will become like that. Extra
real. You'll have to use "reality checks" to know whether it's a dream. That's
usually how you wake up inside a dream to begin with, though. You'll be able
to control some, too.

Lucid dreaming resources will teach you about all that. You'll probably enjoy
it.

~~~
whenchamenia
Lightswitches and digital clocks are common tests, as are punching, jumping
and most kinestetic tasks.

------
568853578
I absolutely love the transition of propofol sedation. It's like the moment
you dive into your pillow after a very, very long tiresome day. Where
sleepiness feels more than justified, and you're allowed to follow.

Weird thing, I always start to talk English (German native speaker) while
drifting away. Since I was a little ashamed of that, I once told the
technician beforehand and he replied it's quite common and a known
observation.

~~~
matt-attack
I’m wondering what exactly is the commonly observed effect. Is it that English
specifically dominates over any language? Or is it the 2nd language, whatever
they may be, that surfaces?

~~~
568853578
He said forgeign language.

I hypothesize a foreign language might require some mental effort and isn't
accessed the same as the native language. The fading consciousness might lose
a native language sooner, maybe.

------
DebtDeflation
Had propofol a few years ago when I went in to get some kidney stones blasted
out. Can confirm what others are saying. They inserted the needle and a few
seconds later I went from fully conscious to waking up at the end of the
procedure with no recollection of time having passed, as if someone toggled my
power switch off and on. When I came to, I was babbling incoherently to the
nurses for a minute or so, but after that I was fully awake and felt as if I
had just woken up from the best, most restful sleep I'd had in a very long
time; it was a very pleasant feeling.

~~~
ak39
Yip. Can concur. Went in once during the first emergency episode and woke up
feeling strangely tranquil. Happy is the only word I’d use during a time of my
life riddled with chaos and uncertainty.

I went under a second time for the removal of the stent and used this second
experience to confirm that it was indeed the anesthetic that confers this
happy feeling post op.

I wouldn’t wish kidney stones for my worst enemies though. That pain is
horrible.

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nvr219
This is the least amount of words I understood in an HN headline ever.

~~~
tptacek
If you trigger memories in a PTSD patient and then knock them out with
propofol, you may disrupt the long-term storage of those memories or even
create a window in which they can be changed. It's Eternal Sunshine of the
Spotless Mind, essentially.

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namenotrequired
Am I understanding correctly that they found they can give you this chemical
and then if you experience negative things you won’t remember them (or you
will but without negative connotations)?

~~~
jazoom
When I was doing my anaesthetics terms we used more than just propofol. We
used a cocktail for various effects. Propofol to knock you out. Volatile gas
to keep you under. Opioid (usually fentanyl) so you don't feel pain.
Suxamethonium to relax your muscles. Benzodiazepine (e.g. midazolam) so you
don't remember anything.

Of course it's more complex than that since most of those also make it easier
to keep you under.

~~~
deskamess
I am amazed we somehow found out about all these concoctions. They seem to go
so far from the norm without killing you. How are they engineered in the first
place?

My moment was not propofol but another medicine for nausea/vomit - it worked
in seconds just when I had resigned myself to throw up. I was shocked. How?

~~~
goldenkey
5-HT3 antagonism.

[https://en.wikipedia.org/wiki/Ondansetron](https://en.wikipedia.org/wiki/Ondansetron)

Usually nausea is caused by the perception that your body "doesn't feel
right." Serotonin is responsible for the feeling of wellbeing. Just so happens
that subreceptor 3 is more about well being feeling of the body :-)

~~~
gurumeditations
So that’s why I get nauseous when I’m hungry.

------
merpnderp
After propofol I came to mid-sentence. I immediately asked how long I’d been
talking, as I had zero recollection of being awake or talking, and was told
I’d been telling jokes non-stop for the last 5 minutes. When I say I have no
memory of that, I mean like I have no feeling I even existed in the period
between telling the doctor I was going under up until I apparently woke and
was well into my spontaneous comedy routine.

------
bookofjoe
Psychiatry is undergoing a phase change, what with
esketamine[Spravato]/ketamine and now propofol[Diprivan] becoming part of
everyday practice. Look for MDMA and psilocybin to join them in the near
future.

------
jazzyjackson
whoa

Wasn't this the plot of the podcast turned TV series Homecoming?

activate a memory, take medicine, suppress memory

rinse and repeat and having cured your PTSD the army can send you back to the
war.

~~~
zadler
Not so sure you’d be “cured”, since PTSD can alter the body’s stress response.

------
et2o
This is interesting. A number of drugs are thought to function similarly from
an interesting mix of classes such as propranolol (a beta blocker) and even
steroids like dexamethasone.

Propofol sedation is a pretty big proposal for something like this so they'd
need a comparative effectiveness trial I think.

------
DiseasedBadger
Imagine what you could do with soldiers if you gave them this every night. I
imagine it'd also work wonders on political dissidents: just keep interviewing
and drugging them until they can't remember their anger.

This is a truly magnificent achievement for all mankind.

------
jokowueu
Imo they should look into isoflorane . Human studies were very promising

[https://www.ncbi.nlm.nih.gov/m/pubmed/23922809](https://www.ncbi.nlm.nih.gov/m/pubmed/23922809)

------
joaomacp
My mother is a nursing assistant at a hospital. She's in the gastro wing where
they do endoscopies and colonoscopies, most times with propofol sedation.

This stuff is true. She tells me people often experience discomfort and pain,
and even complain during the examination (they don't go completely
unconscious), but after they've woken up, they don't remember it! They may
have some lingering pain, but they don't feel bad about the examination. The
doctors say it went well, and they believe it.

------
elevenoh
Seems like most anxiolytic serotonin/downer psychedelics do similarly. (i.e.
ketamine, mdma)

~~~
provemewrong
I wouldn’t call MDMA downer.

~~~
elevenoh
Should have stated anxiolytic or* downer instead of /

~~~
goldenkey
Its a stimulant - amphetamine

------
YeGoblynQueenne
>> We tested whether deep sedation could impair emotional memory
reconsolidation in 50 human participants.

A study on 50 people doesn't sound like it has the statistical power to
predict anything in the general population.

~~~
d33
Depends on how random the group is and how much confidence you want out of
such study.

~~~
sterwill
And how great the effect is. If you recruited only 5 healthy humans at random
and administered a new drug and 100% of them died instantly, you can probably
make some useful predictions.

~~~
YeGoblynQueenne
Yes, and the effect was tiny. See the caption in figure 2 for a summary:

    
    
      Scores (percentage) for each story per group: 
      group A (n = 25 participants) reactivated mean (SEM) = 53.49 (2.29); 
      nonreactivated mean = 59.20 (2.60); 
      group B (n = 24 participants) reactivated mean = 59.52 (1.97); 
      nonreactivated mean = 61.19 (2.11). 
    

That's 6.03% difference between the groups on reactivated means and 2% on the
nonreactivated means. Each group was 25 people.

What's the predictive power of this? What's the explanatory power? What did we
learn? That 25 people reacted a little differently than 25 other people on a
test after the same drug was administered and some more time elapsed between
the times when the two groups took the tests.

There's nothing to see here.

Edit: Btw, both groups received endoscopy and midazolam or phenylpiperidine
derivatives- so not only the effect measured was small it was also not
possible to clearly attribute it to propofol, rather than the endoscopy or the
additional drugs administered.

~~~
sterwill
My comment used a hypothetical toxicity study where 100% of people died
instantly as an example of a very large effect size. It did not address the
Propofol sedation study.

