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Science

The Purpose of Sleep? To Forget, Scientists Say (nytimes.com) 145

Over the years, scientists have come up with a lot of ideas about why we sleep. From a report on NYTimes: Some have argued that it's a way to save energy. Others have suggested that slumber provides an opportunity to clear away the brain's cellular waste. A pair of papers published on Thursday in the journal Science offer evidence for another notion: We sleep to forget some of the things we learn each day (Editor's note: the link could be paywalled; alternate source). In order to learn, we have to grow connections, or synapses, between the neurons in our brains. These connections enable neurons to send signals to one another quickly and efficiently. We store new memories in these networks.
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The Purpose of Sleep? To Forget, Scientists Say

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  • Purpose of sleep (Score:2, Interesting)

    by Anonymous Coward

    Is to create more fake news

    • Actually, if you have ever seen something horendous on the nightly news and woken up the next day without a care in the world. That is what sleep is for. It gives your brain a chance to hide stuff from you. It does this for many reasons. To stop you getting dispare. To stop you trying to solve a problem you don't have the ability to solve, because the energy cost is prohibitive and you can't just keep stacking up the problems you cant solve and run them forever you would stop functioning. This is what
  • Wake me up (Score:4, Funny)

    by gatfirls ( 1315141 ) on Friday February 03, 2017 @02:27PM (#53797495)

    In 4 years please.

    • by gnick ( 1211984 ) on Friday February 03, 2017 @02:33PM (#53797569) Homepage

      Have you tried turning yourself off and on again?

      • by Tesen ( 858022 )

        I suspect there is a lot of self turn on...

      • Tragically, I know too many people who have turned themselves off. Not one has been able to turn themselves back on again.

        Except this one guy about 2000 years ago.

    • Re: (Score:2, Troll)

      Comment removed based on user account deletion
      • Re:Wake me up (Score:4, Insightful)

        by Archangel Michael ( 180766 ) on Friday February 03, 2017 @02:57PM (#53797899) Journal

        If you're implying that Trump is some how anti-semetic or anti-Jewish, may I remind you that his Daughter and Son-in-Law are Jewish. Or is this more of a subtle attempt to brandish him as "Hitler"?

        Hopefully neither is the case. But I do recommend the following link as a read no matter what your political stripe may be. Maybe then we can stop calling everything we don't like "Hitler" or "Nazi"

        https://regiehammblog.wordpres... [wordpress.com]

        • by gnick ( 1211984 )

          If you're implying that Trump is some how anti-semetic or anti-Jewish, may I remind you that his Daughter and Son-in-Law are Jewish.

          I don't think that anyone is implying that Trump's going after the Jews - It's his apparent attitude toward another religious group that has some people calling him out.

          • You mean the 7 countries Obama identified as Terrorist sponsoring countries? Those people?

            • by gnick ( 1211984 )

              You mean the 7 countries Obama identified as Terrorist sponsoring countries? Those people?

              Yes, of course those people. Are you saying that there's no objection being voiced to a perceived attitude toward Islam? I didn't think I was being that controversial - I wasn't even trying to justify the objection.

        • Re: (Score:2, Insightful)

          Comment removed based on user account deletion
        • by quenda ( 644621 )

          If you're implying that Trump is some how anti-semetic or anti-Jewish ...

          Trump is not anti-Jewish*, but he sure does not like the other semites. [google.com.au] Excpet the Saudis - they're good for business. Love the Untied States.

          * Trump made Steve Bannon leave his white hood at home.

        • by Spaham ( 634471 )

          To those who say that Hitler only likes blond aryans, let me remind you that he is a short black haired man.

    • Re:Wake me up (Score:5, Insightful)

      by NotInHere ( 3654617 ) on Friday February 03, 2017 @02:40PM (#53797663)

      Great idea, but you'd miss the elections, and if everyone except the Trump supporters did this, you'd have to sleep for another 4 years.

    • you mean 8 years, of course... he's already planning his reelection.

      https://nypost.com/2017/02/01/trump-has-already-raised-16m-toward-re-election/

    • by p0p0 ( 1841106 )

      8 years

      FTFY

    • by quenda ( 644621 )

      In 4 years please.

      If a giant asteroid was a heading toward Earth, would you rather use what little time you had left, or sleep through it and die without knowing?

    • by ebvwfbw ( 864834 )

      Just in time for the next 4 years of Trump!

      You missed the Evita style funeral of Hillary (both fascist despots) and Bill's funeral (Juan Perone, another fascist). Their "foundation" was taken apart just as the Perone's charity was. In a few years Andrew Webber will write another musical about them and their trail of dead bodies. It'll probably star Lady Gaga as the dominatrix and Tom Hanks as the dominated Bill.

      Also, missed George Soros' funeral, right after he did the evil guy on the next Star Wars movie.

  • All of the above (Score:4, Interesting)

    by religionofpeas ( 4511805 ) on Friday February 03, 2017 @02:34PM (#53797595)
    It seems rather obvious that the primary reason for sleep is to conserve energy when being awake isn't very useful (at night when you can't see anything). It also makes sense that the body has then evolved to do other useful things while sleeping.
    • It seems rather obvious that the primary reason for sleep is to conserve energy when being awake isn't very useful (at night when you can't see anything). It also makes sense that the body has then evolved to do other useful things while sleeping.

      Doesn't pass the basic acid test. Why do nocturnal creatures sleep? The night is when they are active and they can see perfectly fine in the day. No need for sleep at all according to your theory. :)

  • I thought that was what the weekends were for. I keep a dead tree notebook at work to write down what I did each day and remind myself what I did from the week before. Otherwise, on Monday mornings, I'll have no clue to what to do.
  • by olsmeister ( 1488789 ) on Friday February 03, 2017 @02:35PM (#53797605)
    I thought that was the purpose of whiskey.
    • by Tablizer ( 95088 )

      I thought that was the purpose of whiskey.

      But it doesn't last.

      "Trump who? Oh, right, that guy. Another round, please!"

  • by Anonymous Coward on Friday February 03, 2017 @02:41PM (#53797685)

    Not getting any sleep is fatal. The theory that sleep's main function is "to forget" doesn't explain that. Of course, the post didn't claim that was its sole function, but I'd say it implied it. Scientific American had an article on sleep last year which favored the garbage removal theory. It's not very smart to think that sleep has a single purpose, imho. The fact that all mammals sleep, (some only half a brain at a time) and as far as I know all birds, reptiles, amphibians, and some (not all) fish sleep. Plus some insects enter a state similar to sleep, as do roundworms. Such a broad adoption clearly indicates it has a very strong evolutionary driving/survival force behind it.

    • Not getting any sleep is fatal. The theory that sleep's main function is "to forget" doesn't explain that. Of course, the post didn't claim that was its sole function, but I'd say it implied it.

      Well, I'd say the summary implied that this may be sleep's primary function, probably not the "sole" one. But I take your point.

      Scientific American had an article on sleep last year which favored the garbage removal theory.

      Yes, the theory itself is hardly new. These two new studies seem to support it. It does seem to make intuitive sense, since a lot of our brain's activity has to do with getting rid of all the "noise." People who are working with AI these days realize how difficult it can be to get a system to sort out the patterns from the noise, particularly when it comes to greater abstractio

    • Pretty much every documentary, and article that I've come across over the last 10 years on the "purpose of sleep|dreaming" say nearly the exact same thing. Maybe these "researchers" could build on what is already known instead of regurgitating known facts.

      * Forget unimportant crap.
      * Solidify New Memories.
      * Clear out built-up toxins.
    • by Anonymous Coward

      You are right we would die.
      Why? Because lots and lots of bodily maintenance happens when we're sleeping. Cells can't rebuild fast enough or old cells thoroughly flush out when we're awake because they're actively managing a busy body. But when we shut down... the lack of activity allows healing, scrubbing, and other organic functions to take place with great results. In a more /. example would you prefer your computer do heavy background functions while you are working, slowing all your efforts by half?

    • "Not getting any sleep is fatal."

      We don't know much about sleep, and we don't even know if sleep deprivation can be lethal.

    • by cats-paw ( 34890 )

      i think it's more likely that during sleep, as your body resets the systems it needs things that have not been strongly re-inforced are forgotten.

      as you point out, sleep is wired in at an extremely low level.

      researchers don't seem to assign as much importance to that fact as you would think it deserves.

    • Not getting any sleep is fatal. The theory that sleep's main function is "to forget" doesn't explain that.

      Conceivably, it does. This theory goes that sleep makes us forget in order to do "housekeeping" for the brain. If the brain gets too cluttered, runs this line of thinking, it starts failing to function. Several neural failure could indeed lead to death.

    • Scientific American had an article on sleep last year which favored the garbage removal theory.

      Yet more evidence for this theory:

      http://neurosciencenews.com/sl... [neurosciencenews.com]

      As someone who's done plenty of sleep deprivation and polyphasic sleeping, I'm about pretty sure I can actually feel the garbage being removed. It mostly happens in the first 60-90 mins of sleep. If one is woken between 30 mins and 60 mins, one's mind tends to be missing several functions. ;)

      • by epine ( 68316 )

        I have a circadian rhythm disorder. Not that long ago I free ran on my innate 25.5 hour circadian day for three years, before I discovered that only sustained release melatonin is able to fix my problem (the shortest circadian day I achieved on any dose/formulation of non-SR mel was 24.15 hours, which required me to discontinue for two out of every five-six weeks for vertical retrace).

        2016 was the first year of my adult life where I didn't lose entrainment with the calendar day.

        But it's still not a bed of

    • The purpose of sleep is to allow your eye 'looking beams' to recharge. If you don't recharge them they will slowly lose power and your vision will become darker and darker (for an average person, this will happen in the evening). During winter the cold will also drain your eye 'looking beams' quicker - hence your vision will become darker earlier in the evening.

  • There are certainly embarrassing events in my past that I would prefer to forget, but I don't seem to be able to.

    Why isn't it working for me?

    • No kidding. For me, the more I try to avoid thinking about the embarrassing thing, the more acute it gets as my brain forces me to relive the moment over and over again.

      TBH, this is why I don't hang around people, I always end up saying or doing something that I later analyze and construe as hyper embarrassing, even if it wasn't really. It's probably a medical condition of some kind...

      Sometimes (a lot actually) the thought will come on so suddenly and so strongly that I make a weird non-verbal sound, whimpe

  • by Anonymous Coward

    I don't need sleep to forget things.

  • by Anonymous Coward on Friday February 03, 2017 @02:46PM (#53797751)
    Proof that God is a hack and couldn't write a kernel that manages much more than a 48h uptime before it needs a reboot. I bet all the kids in other galaxies with cooler Gods are laughing at us.
  • Please try and write summaries that at least get somewhere close to the crux of the story, and don't just trail off mid-concept.

    In 2003, Giulio Tononi and Chiara Cirelli, biologists at the University of Wisconsin-Madison, proposed that synapses grew so exuberantly during the day that our brain circuits got “noisy.” When we sleep, the scientists argued, our brains pare back the connections to lift the signal over the noise.

  • A nightly (for most of us) redundancy check and defrag of the ol' noodle?
  • by gurps_npc ( 621217 ) on Friday February 03, 2017 @03:21PM (#53798163) Homepage

    I can think of at least 5 reasons for sleep off the top of my head, and several have nothing to do with the brain:

    1) Eliminate unwanted memories, like this study suggested.

    2) Reduce consumption during periods of low resources, enabling longer life. I.E. Consume fewer calories in winter.

    3) Rest the body giving it time to repair minor every day issue without constant strain.

    4) Time for the unconcious brain to do deep thinking and solve long term problems

    5) To allow the body to expand all it's resources to fix major illnesses, such as Small Pox, because it literally takes EVERYTHING we got.

  • by jenningsthecat ( 1525947 ) on Friday February 03, 2017 @03:28PM (#53798229)

    FTA:
    "That night, the scientists injected a chemical into the brains of some of the mice. The chemical had been shown to block neurons in dishes from pruning their synapses. The next day, the scientists put all the mice back in the chamber they had been in before. Both groups of mice spent much of the time frozen, fearfully recalling the shock. But when the researchers put the mice in a different chamber, they saw a big difference. The ordinary mice sniffed around curiously. The mice that had been prevented from pruning their brain synapses during sleep, on the other hand, froze once again. Dr. Diering thinks that the injected mice couldn’t narrow their memories down to the particular chamber where they had gotten the shock. Without nighttime pruning, their memories ended up fuzzy."

    I'm far, far away from being a neurologist, so I may be totally off track here. But these results remind me of what PTSD sufferers go through, and I have to wonder if they're related. Might the emotions experienced in response to traumatic events, be so strong as to alter neurons, synapses, or brain chemistry in such a way that the synapses aren't pruned in the normal way by sleep? Or perhaps the loss of sleep that results from traumatic experiences results in something like setting the 'immutable' bit on a file?

  • So sleep is just another form of cache cleaning?
  • Zombie Nation describes the harm sleep deprivation is doing to the United States. https://drive.google.com/file/... [google.com]
    • No mod points, so I'll just say "thank you" for the article instead.

    • Zombie Nation describes the harm sleep deprivation is doing to the United States.

      I was going to ask what the hell a bunch of German techno producers would know about it, but I guess they've spent a few late nights in clubs over the years.

      (And yeah- I know. I used to think that too, but "Kernkraft 400" was actually the name of the song...)

    • by MrKaos ( 858439 )
      Wow, this is really great - thanks.
  • Farnsworth: And what makes my engines truly remarkable is the afterburner, which delivers 200% fuel efficiency.

    Cubert: That's especially impossible.

    Farnsworth: Not at all. It's very simple.

    Cubert: Then explain it.

    Farnsworth: Now that's impossible! It came to me in a dream and I forgot it in another dream.

  • WTF am I reading? Hipster's "science" newsletter.
  • I also seem to recall reading that when you sleep (properly), your brain also gets flooded with cerebrospinal fluid, which cleans a type of "plaque" from between pathways in the brain. This plaque has been seen as possibly contributing to various mental/cognitive degenerative conditions

    I can't find the exact thing I read previously, but here [scientificamerican.com] appears to be an article on it.

    • your brain also gets flooded with cerebrospinal fluid, which cleans a type of "plaque" from between pathways

      So, you're saying that cerebrospinal fluid is basically mental floss [mentalfloss.com] then?

      • by phorm ( 591458 )

        I'm not a brain scientist, but basically sounds something like Plax for the ol' grey matter.

  • I forgot what I was going to say here.

  • Some have argued that it's a way to save energy. Others have suggested that slumber provides an opportunity to clear away the brain's cellular waste

    Odd juxtaposition. Let's put it this way with some fake news. There once was a time when all there was was day. Then suddenly God made night. In a first stage the Day-beings spent their nights waiting, saving energy and keeping save. But in a later stage they started doing too much of some activities during the day because they could postprocess/recover/clean

  • The real question is, "why are we conscious?"
  • Thank god for that, I don't need to join the Foreign Legion after all.
  • "The Purpose of Sleep? To Forget" "We store new memories in these networks."
    To forget is to store new memories?
  • Sleep that knits up the ravell'd sleeve of care,
    The death of each day's life, sore labour's bath,
    Balm of hurt minds, great nature's second course,
    Chief nourisher in life's feast,--

    • To die, to sleep--
      No more--and by a sleep to say we end
      The heartache, and the thousand natural shocks
      That flesh is heir to. 'Tis a consummation
      Devoutly to be wished. To die, to sleep--
      To sleep--perchance to dream: ay, there's the rub,
      For in that sleep of death what dreams may come
      When we have shuffled off this mortal coil,
      Must give us pause.

      Hamlet's Soliloquy

  • ... rm -rf /

    Zzzzzzz

  • The need for "sleep" (regular periods of markedly reduced activity, distinct from mere rest) is virtually universal across the vertebrate sub-phylum at least, with a last common ancestor 500 million years ago, found in every family (though not necessarily obviously so in every species).

    This extraordinary common pattern in creatures with radically different environments and life habits, persisting over such a vast stretch of evolutionary time, alone suggests there is not "one reason" for it, and indeed a l

    • What all share is the rotating earth with (nearly) half day and half night. And most of these species will respond to light (ie have some form of eyes/visual processing). It may be interesting to study creatures/life deep under ocean (non dependent on sun/light/day/night) whether they too have any form of "sleep". The point is your light stimulus changes regularly every 12 hours - it only makes sense to optimize your internal processing based on this cycle. And all life is doing that.
  • I think this study actually raises more questions than it answers: If we sleep to forget, than what is the purpose of drinking?

  • I sleep because I am sleepy. (But only if I manage to shut down the web browser.)
  • What I found with my experimentation is I feel fresh based on how many hours I had visual stimuli off; it doesn't matter if I sleep or lying staring the darkness. I can even afford some audio input/output (listen to songs or even sing/talk along - yeah may sound like a mad man). The crucial piece is my visual cortex in brain is kinda put in a lower power mode. Then even if i really sleep only a few hours say 3 or 4, I still feel fresh. The contrary is true as well. If I am busy in computer or phone and slee
  • I'd always thought sleep was for helping to retain memories, not erase them.

    During sleep, we are not recording nearly as much data as when awake, giving the brain the opportunity to prioritize which earlier experiences need to be retained in long-term storage.

    Many theorize that during REM sleep, while dreaming, we are actually re-living various experiences gathered throughout the day. By re-examining these experiences, they have a better chance of being retained long-term.

    Remembering a pretty suns

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