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>One of the big, unsolved mysteries in science is exactly why humans and other animals sleep. There are plenty of hypotheses: it’s believed sleep is important in letting our organs repair themselves and is key in developing memories. But it’s unclear why that much-needed maintenance only happens after we fall into an unconscious state, making us vulnerable to predators. One way of solving the riddle of sleep is to investigate its origins, and a new study in the journal Nature involving zebrafish reveals that the pattern of sleep found in humans and many other animals evolved at least 450 million years ago.

>Researchers built a special fluorescent light-sheet microscope that could image the entire tiny fish down to single cells. They also genetically engineered fish so their muscles and neurons would light up in the presence of calcium, which is released when those cells are active. They then immobilized sleeping two-week-old zebrafish, which are transparent, in an agar solution. They were also able to capture the heart rate, eye movement, muscle tone and other data using a fluorescence-based sleep study apparatus they developed.

https://www.smithsonianmag.com/smart-news/study-little-fish-show-sleep-least-450-million-years-old-180972625/
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>>10799644
>They found that the fish went through sleep cycles similar to humans, including periods the team dubbed “slow burst sleep” and “propagating wave sleep.” While they did not exhibit random eye movement (REM), which is ubiquitous in mammals, their eyes did roll back in their sockets. Their brain and muscle signatures, however, as well as the hormones that regulate sleep were all similar to those found in mammals. “They lose muscle tone, their heartbeat drops, they don't respond to stimuli—the only real difference is a lack of rapid eye movement during REM sleep,” senior author Philippe Mourrain of Stanford University says in a press release.

>The study suggests that the basics of sleep emerged before mammals and fish diverged from an ocean-dwelling common ancestor 450 million years, about 150 million years earlier than previously believed. “These signatures [of sleep] really have important functions — even though we may not know what they are — that have survived hundreds of millions of years of evolution,” the study’s first author Louis Leung, a sleep researcher at Stanford, tells Tina Hesman Saey at Science News.
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>>10799647
>“We truly did not expect to find so many similarities with human and mammalian sleep,” Mourrain tells Kashmira Gander at Newsweek. “To see, in a live vertebrate, the complex choreography of brain and muscle activity during wake-sleep transitions and sleep was mind-blowing.”

>The finding means that researchers may be able to use the little fish—already a staple in the science labs—to look into sleep disorders and to test sleep drugs. Currently, many studies rely on mice, which are nocturnal, to investigate sleep. Leung says in the press release that the fish might be a better stand-in for humans. “Because the fish neural signatures are in essence the same as ours, we can use information about them to generate new leads for drug trials,” he says. “As zebrafish are diurnal like humans, it’s perhaps more biologically accurate to compare fish sleep with humans’ for some aspects.”

>While the new technology used to image the sleeping fish is being widely praised, Jenny Howard at National Geographic reports that not everyone thinks the sleep cycles in the fish are analogous to mammals. For one thing, sleep scientist Jerry Siegel at the University of California, Los Angeles, points out that the researchers looked at very young fish, and that sleep patterns in juveniles and adults are almost universally different in the animal kingdom.
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>>10799648
>“You can’t just say sleep is sleep,” he says, pointing out that among mammals sleep patterns are incredibly varied with some species getting three hours of shut-eye per day and others drifting off for 20 hours. Some animals have REM cycles, and some do not.

>Mourrain, however, is more optimistic about the little swimmer's use in sleep research, even if the zebrafish’s nightly routines isn’t exactly the same as humans. “People forget that vertebrates are all very similar in their body organization and organs,” he tells Newsweek’s Gander. “We not only share a backbone protecting our spinal cord, the rest of the brain and neurochemistry allowing neurons to communicate is extremely conserved.”

>He points out that the fish are already used in lots of medical research, including cardiovascular and cancer research, and believes this study shows they could also be used in sleep and neuroscience studies as well.
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>0 replies on very interesting topic
absolute brainlet board.
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>>10801767
they are sleeping dude
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>>10801767
maybe it has something to do with OP improperly greentexting an entire article
or maybe it's just a boring article, which unfortunately also implies that you are boring because you described it as interesting
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>>10801781
Basically this. I came here to ask how they breath if their stuck in agar.
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>>10801794
>their
They're
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>Sleep Is at Least 450 Million Years Old
This appears to me more like evidence of convergent evolution.
Even octopus have been show to have what they think appears to be REM sleep. Think of that. An invertebrate animal that can dream. Maybe sleep isn't a 450 million years old evolutionary quirk, but some type of convergent evolution that all animals with sufficient brain mass must do.

Sleep is used for proper activation of the glymphatic system. So logically, any animals with enough brain mass to allow brain waste to accumulate is going to need a period of time that cleans/drains the waste. Hardly proof that sleep is 450 million years old. Just that it's logically something any animal will evolve learn to do, eventually... with time....
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>>10799644
>zebra fish is entombed alive in agar
I can't imagine how many vengeful zebra fish and lab rats are going to be waiting for scientists in hell.
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>>10801819
If the function is so essential the performance of complex life then its almost certain that its preserved and so it probably is a case of a synapomorphy. could say the same thing for glycolysis but its more likely to be an ancestral trait than a case of convergent evolution
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>>10801819
I was thinking the exact same thing.
They need more evidence to show that the functions of sleep are not convergent
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>>10801825
They don't notice it, they're sleeping
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>>10801853
How do they breath, though?
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>>10801926
the scientists ran little water tubes to their gills, you'd know this if you'd read the paper
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>>10801932
It's not an interesting enough paper to read. Thanks though.
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>>10801819
yes, but apperently researchers haven't found an ancestor with diverging behavious yet, so there is nothing to converge to.
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>>10801794
fish dont breathe.

>>10801819
If all animals do it then why would you think its convergent and didnt just evolve in an ancestor if it seems so important to evolve in the descendents. Youre also making your assumption based on what you think sleep is for which we dont really know atm but I dont think people think draining waste is the leading hypothesis.
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>>10801767
>stanford university press release

can you keep marketing and communication fags out of science pls thx



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