
Hunger Is a Gatekeeper of Pain in the Brain - Semirhage
https://www.nature.com/articles/d41586-018-04759-0
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krupan
Early comments make me think people didn't read the article. Short summary:
hunger reduces long-term inflammatory pain but reduce short-term acute pain
was not reduced.

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wallace_f
When I first read the title I thought of my observation with the migraines I
get. Personally, migraine _pain_ only onsets when 'everything is ok,' in terms
of safety, stress, food and hydration; but the other symptoms will start at
any time.

For example, while rock climbing once, I was getting down from the top of a
mountain, seeing those 'squirlly refractive light worms' in my vision that
some people with severe migraines get. I had all the symptoms of having a
migraine--and was lucky I didn't die on that mountain--but the debilitating
pain only came when I was down, in the car, away from danger, with food and
water. This is how it always is.

Given this experience, I believe there must be a lot more to the
psychological-physical aspect if interpretations of pain than what is shown
here, and personal experiences may be why others are jumping to conclusions.

Also: those poor mice

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usaphp
> seeing those 'squirlly refractive light worms' in my vision that some people
> with severe migraines get

Those worms are simptom that the migraine is coming, I had terrible headache
several hours after I saw this light worms.

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mrob
The medical name for the light worms is "scintillating scotoma". The Wikipedia
article includes some artist's impressions:

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

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danharaj
I wonder if there are people who overeat because of chronic pain.

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amerkhalid
it would be other way around, they will eat less to dampen chronic pain.

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sametmax
The thing is, with health, if the effect of you action are not immediat, you
are much less likely to do the right thing.

E.g : i know that if a drink a lot of raw milk i generally get a migraine. But
it happens 24 to 48 h later. So i still drink milk from time to time because
i'm not punished immediatly. It's future me's problem.

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yellowapple
"The body’s basic needs include a timely supply of nutrients and the avoidance
of tissue damage, which are signalled in the brain by hunger and pain,
respectively. But these needs cannot be fulfilled simultaneously, because
their resolution involves mutually exclusive behaviours."

Hold up. Why are these mutually-exclusive? Is nutrient intake not a subset of
tissue damage avoidance?

I think I get the gist of what these sentences are _trying_ to say (acute pain
takes precedence over hunger, which takes precedence over chronic pain), but
that's not what "mutually exclusive" means.

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erentz
I took it to be in more evolutionary terms:

* If you’re hungry you need to move to find food

* If you’re in chronic pain you need to rest to heal

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eloff
Consuming food is an inherently inflammatory process. Could this not explain
the results?

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sridca
Fasting is known to reduce inflammation

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vinayan3
If you have persistent stomach pain not eating can sometimes do the trick if
you suffer from digestive inflammation. The inflammation can be triggered by
eating the wrong combination and or quantities of certain foods.

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intralizee
I'm curious if the word, "hunger" is a poor choice in comparison of using
"lack of food" and because I rarely eat in comparison to most people. I've
become accustomed to not having hunger overtime as a result of fasting and
otherwise one meal per day. I do believe the gateway of pain is true.

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croon
I've done the same over many years, and can confirm being accustomed.

I have very different sensations now signalling "lack of food" and "craving
for stuff I don't need", and the latter isn't as persuasive anymore.

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holri
Nice that the very old natural medicine knowledge of starving and chronic pain
reduction is confirmed. Unfortunately the exploration of old natural medicine
knowledge is not well funded because there is no money to earn.

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DoctorOetker
so incoming pain signal is filtered through low-pass and high-pass filters,
the intermediate output from the low-pass is modulated by hunger and then
added to the unmodified high-pass signal. this sum is the effective or
subjective pain signal.

perhaps this could be used for online learning neural networks (with neural
plasticity): goals are eventual and dont need to be accutely achieved upon the
moment of forming the goal (i.e. feeding can be postponed), while punishment
of the neural network should be accute in order to focus on the problem while
any information related to the problem is still present in the brain.

~~~
firethief
I think low-pass/high-pass is sort of a misleading simplification. When they
say "chronic" pain they're referring to inflammatory pain, which is
distinguished from "acute" pain by its source, not its time course. (I think.
Not a biologist.)

~~~
contoraria
Different sources might use different time codes. Anyway, inflammation likely
attacks all kinds of sensors and perhaps nerves directly, so the signal is
noisy, and the high frequency constituents very unstable. Whereas functioning
receptor networks likely fire in ensemble, so that signal should be kind of
clear. The functionally intact rim of an inflammation is a comparably large
area, so that would correspond to a low frequency signal. Although, it's much
more complicated, surely, I wouldn't know.

Also, hunger after a long time becomes a dull feeling, too. Less energy ->
longer time to light a synapse.

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known
"Our minds are like our stomachs; they are whetted by the change of their
food, and variety supplies both with fresh appetites" \--Quintilian

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pbhjpbhj
This is expected: if you get very hungry then food acquisition is more
important than avoiding relatively minor bodily damage. If damage is severe,
then it can override the need to get food.

If it were not this way we'd be pretty rubbish at surviving.

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nuclx
Somewhat related recommended read: Hunger (Knut Hamsun)

[1]
[https://www.goodreads.com/book/show/32585.Hunger](https://www.goodreads.com/book/show/32585.Hunger)

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alexandercrohde
Is it possible the particular rat-food causes inflammation? I'd imagine
whatever they're being fed isn't their natural diet (i.e. organic raw meat
etc)

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banach
After reading Peter Singer's Animal Liberation, I can't help but recoil in
disgust at what it must have taken to produce the results for such a paper.
Sure, this is interesting, but is it really worth the cost? Did the
researchers or those who funded the research even reflect on it?

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firethief
It's a one-time cost for knowledge that will have benefits indefinitely. I
don't eat or wear animals, but I'd holocaust a million rats to solve the
opioid epidemic.

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komali2
Is the barrier for you species difference?

For example, medical insights provided by Nazi scientists, and to a lesser
extent Japanese ones, were provided by tests on human subjects with often
fatal results.

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nordsieck
> Is the barrier for you species difference?

I haven't met a person for which this isn't true.

From my conversations with other people, the hierarchy of care is roughly:

Humans > large mammals > small mammals / cephlopods > birds / large reptiles >
small reptiles / fish > large insects / trees > small insects / spiders /
plants > yeast / fungi / bacteria

~~~
komali2
If this is true then why does non consenting human experimentation happen
ever?

In any case, hierarchies like that are almost totally arbitrary, like anything
about a culture.

I'm just poking the bear here and seeing what comes out. Let's play with this
more.

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Tomminn
Yup, totally arbitrary. That's why I prefer the poetry yeast writes about the
beauty of the universe and the pain of existence to that written by humans.

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komali2
Is your point that only humans have culture? There is evidence of culture and
learned behaviors in animals as simple as birds.

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Tomminn
My point is that the hierarchy is ordered by increasingly sophisticated
internal conscious experience. This is the least arbitrary thing ever when it
comes to concern around suffering.

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komali2
My argument was more that there is no association between a theoretical
"hierarchy of care" and actual, real brain sophistication. If there were,
people would for example eat cats before they ate pigs.

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pbhjpbhj
Cats don't have much meat, I imagine larger mammals are farmed because they're
large. But inhibition to eating pigs would be larger than that for eating
cats, I'd agree on that.

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empath75
Eating disorders and self-harm seem to go together a lot so it make sense that
there’s an underlying connection between pain and hunger.

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21
Except that the paper seems to find the reverse connection - self-harm is
typically acute, and this is not inhibited by hunger.

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yellowapple
Reverse that a bit more: self-inflicted acute pain overrides/inhibits hunger.

