4 ms·

What about this? Sleep Drives Metabolite Clearance from the Adult Brain (2014) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3880190/ https://www.ncbi.nlm.nih.

What about this? Sleep Drives Metabolite Clearance from the Adult Brain (2014) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3880190/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3880190/ > Using real-time assessments of tetramethylammonium diffusion and two-photon imaging in live mice, we show that natural sleep or anesthesia are associated with a 60% increase in the interstitial space, resulting in a striking increase in convective exchange of cerebrospinal fluid with interstitial fluid. In turn, convective fluxes of interstitial fluid increased the rate of β-amyloid clearance during sleep. Thus, the restorative function of sleep may be a consequence of the enhanced removal of potentially neurotoxic waste products that accumulate in the awake central nervous system.

keepamovin 2y ago
Exactly, the flushing effect. Which you can also feel when you do some forms of meditation :)
- jcutrell 2y ago
  I'm curious - do you have a physical sensation when this happens to you? Is there any evidence to support this claim? I ask because I often feel similar to brushing my teeth when I meditate, it's hard to explain though.
  - lukan 2y ago
    I can relate, but I interpret it as mental cleaning. Letting go of garbage thoughts etc, not literal toxins through the blood, but I assume it also helps this process, by relieving of stress. A body under stress works intentionally different, than a relaxed body. (Stress means some kind of threat, not the time to do cleaning)
    - keepamovin 2y ago
      Hm, there's that, sure. But I get it physically tho, too. I actually feel this: the pumping. It's only a certain type of focus tho. You may not yet have attained it, or perhaps not everyone is physically capable. But I'm happy to try to teach you to do it: reach out to me heh :)
  - keepamovin 2y ago
    Brushing your teeth? That's interesting heh! :) On that: a buzzing sensation in your teeth? Yeah, I can relate. I think it's down to increased sensitivity to the nerves in your teeth that you normally don't pay attention to, but can be apparent when modifying your attention as in meditation. It could be something else, tho! :) To your question on me: I feel this physically. This is not a 'claim', it's evidence: that I'm saying this to you.
- lm28469 2y ago
  You have no physical sensors that would allow you to "feel" events up there.
  - adammarples 2y ago
    by what sense does one 'feel' tired?
  - Lutger 2y ago
    Not literally, though 'feeling' does a lot of work in that sentence and rightly so. You don't exactly have a physical sensor to 'feel' sad either, which also happens up there mostly, but still people usually accept that we can 'feel' the experience of sadness. Becoming aware of mental states influencing perception is how you register events up there (using meditation), which is what 'feeling' means in this context.
    - lm28469 2y ago
      You can also feel things which don't exist, or not feel thing which exist, that's not really a basis for scientific discussions Your eyes can't feel infrared yet they exist, and your eyes can be tricked into feeling movement when there is none (optical illusions) I can find you people who feel the influence of Saturn on their mood... I'm always wary of people using scientific lingo to "prove" their "feelings"; "flushing", "waves", "energy", "toxins", it's way too easy to fall into new age mumbo jumbo
      - keepamovin 2y ago
        It seems you don't trust your capacity for feeling. You need to develop that more, then maybe you will understand. What you say is common among people who have not learned yet
    - keepamovin 2y ago
      Yes, I literally feel the flushing. And I also hear what you say about becoming aware of subtleness to expand your awareness. This can also include physical sensations (not saying it’s the same thing as flushing, but), such as: feeling your heartbeat, feeling your blood pumping around. All of which I’m aware of, but I wasn’t before. Thank you for your supportive comment :)
freddie_mercury 2y ago
That paper is referenced in the one linked. The authors are not unaware of it.
- coldtea 2y ago
  And? Does it succesfully refute it? Or is the new study just another study with bad methodology that wont be replicating? Or maybe the first one is? Individual studies aren't worth considering, especially after they just came out. Call me when they have settled about it, 10+ years from now.
  - wzdd 2y ago
    The way they refute it is interesting. > Those authors observed that fluorescent dyes injected into the cerebrospinal fluid (CSF) via the cisterna magna penetrated further into the cortex during sleep and anesthesia. They interpreted this as showing that molecular movement into the cortex must be faster during these states. However, the concentration of dye in any brain region will always be the difference between its rate of arrival and its rate of departure and so increased dye penetration in sleep and anesthesia can be equally well explained by a reduced rate of clearance rather than an increased rate of entry. So the previous paper assumed that the presence of dye further into the brain meant more clearance, but these authors point out that the presence of more dye could mean less clearance (because if the fluid isn't being replaced as quickly the dye can simply diffuse further). The previous authors also injected dye into the CSF, which complicates matters as the CSF is moving both into and out of the brain all the time. However: > Our data in Figs. 2 and 3 show that, averaged across the brain, clearance is reduced by both sleep and anesthesia ... if you just focus on average dye concentration in the brain, and you inject the dye directly into the brain (the parenchyma) rather than into the CSF, the mean concentration is higher after a period of sleep than it is after a period of wakefulness. Which suggests less clearance, rather than more clearance, during sleep.
    - deleted 2y ago
      [deleted]
  - 2y ago

keepamovin 2y ago

Exactly, the flushing effect. Which you can also feel when you do some forms of meditation :)

jcutrell 2y ago
I'm curious - do you have a physical sensation when this happens to you? Is there any evidence to support this claim? I ask because I often feel similar to brushing my teeth when I meditate, it's hard to explain though.
- lukan 2y ago
  I can relate, but I interpret it as mental cleaning. Letting go of garbage thoughts etc, not literal toxins through the blood, but I assume it also helps this process, by relieving of stress. A body under stress works intentionally different, than a relaxed body. (Stress means some kind of threat, not the time to do cleaning)
  - keepamovin 2y ago
    Hm, there's that, sure. But I get it physically tho, too. I actually feel this: the pumping. It's only a certain type of focus tho. You may not yet have attained it, or perhaps not everyone is physically capable. But I'm happy to try to teach you to do it: reach out to me heh :)
- keepamovin 2y ago
  Brushing your teeth? That's interesting heh! :) On that: a buzzing sensation in your teeth? Yeah, I can relate. I think it's down to increased sensitivity to the nerves in your teeth that you normally don't pay attention to, but can be apparent when modifying your attention as in meditation. It could be something else, tho! :) To your question on me: I feel this physically. This is not a 'claim', it's evidence: that I'm saying this to you.
lm28469 2y ago
You have no physical sensors that would allow you to "feel" events up there.
- adammarples 2y ago
  by what sense does one 'feel' tired?
- Lutger 2y ago
  Not literally, though 'feeling' does a lot of work in that sentence and rightly so. You don't exactly have a physical sensor to 'feel' sad either, which also happens up there mostly, but still people usually accept that we can 'feel' the experience of sadness. Becoming aware of mental states influencing perception is how you register events up there (using meditation), which is what 'feeling' means in this context.
  - lm28469 2y ago
    You can also feel things which don't exist, or not feel thing which exist, that's not really a basis for scientific discussions Your eyes can't feel infrared yet they exist, and your eyes can be tricked into feeling movement when there is none (optical illusions) I can find you people who feel the influence of Saturn on their mood... I'm always wary of people using scientific lingo to "prove" their "feelings"; "flushing", "waves", "energy", "toxins", it's way too easy to fall into new age mumbo jumbo
    - keepamovin 2y ago
      It seems you don't trust your capacity for feeling. You need to develop that more, then maybe you will understand. What you say is common among people who have not learned yet
  - keepamovin 2y ago
    Yes, I literally feel the flushing. And I also hear what you say about becoming aware of subtleness to expand your awareness. This can also include physical sensations (not saying it’s the same thing as flushing, but), such as: feeling your heartbeat, feeling your blood pumping around. All of which I’m aware of, but I wasn’t before. Thank you for your supportive comment :)

freddie_mercury 2y ago

That paper is referenced in the one linked. The authors are not unaware of it.

coldtea 2y ago
And? Does it succesfully refute it? Or is the new study just another study with bad methodology that wont be replicating? Or maybe the first one is? Individual studies aren't worth considering, especially after they just came out. Call me when they have settled about it, 10+ years from now.
- wzdd 2y ago
  The way they refute it is interesting. > Those authors observed that fluorescent dyes injected into the cerebrospinal fluid (CSF) via the cisterna magna penetrated further into the cortex during sleep and anesthesia. They interpreted this as showing that molecular movement into the cortex must be faster during these states. However, the concentration of dye in any brain region will always be the difference between its rate of arrival and its rate of departure and so increased dye penetration in sleep and anesthesia can be equally well explained by a reduced rate of clearance rather than an increased rate of entry. So the previous paper assumed that the presence of dye further into the brain meant more clearance, but these authors point out that the presence of more dye could mean less clearance (because if the fluid isn't being replaced as quickly the dye can simply diffuse further). The previous authors also injected dye into the CSF, which complicates matters as the CSF is moving both into and out of the brain all the time. However: > Our data in Figs. 2 and 3 show that, averaged across the brain, clearance is reduced by both sleep and anesthesia ... if you just focus on average dye concentration in the brain, and you inject the dye directly into the brain (the parenchyma) rather than into the CSF, the mean concentration is higher after a period of sleep than it is after a period of wakefulness. Which suggests less clearance, rather than more clearance, during sleep.
  - deleted 2y ago
    [deleted]
- 2y ago