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  • [♩INTRO]

  • When you were a kid, you probably learned to talk by imitating others.

  • Like, after hearing people sayBye bye!” enough times,

  • you finally learned to make those sounds yourself

  • to the delight of everyone around you.

  • But what if there were another way?

  • What if someone could shine a light on your brain,

  • and you'd suddenly know the foundations of language?

  • Well, that sounds kind of ridiculous, but that's basically what researchers did

  • in a study published last week in the journal Science.

  • But...with birds.

  • They showed that songbirds could learn parts of their courtship song

  • after having it beamed into their brains.

  • And while this method will probably never catch on in humans,

  • it could help us understand how we learn to speak in the first place.

  • Now, at first, this research might seem bizarre...maybe even a little bit absurd,

  • but the goal was actually pretty simple: The researchers wanted to know

  • what pathway in the brain is needed to learn something through imitation.

  • This work is still in the early stages, so instead of experimenting on humans,

  • the study used male zebra finches.

  • These are small, pretty cute birds that learn their songs

  • by listening to and imitating older birds.

  • Past research has suggested that at least some of this process

  • is affected by a pathway between two of their brain regions:

  • the NIf, and the higher vocal center, or HVC.

  • But it hasn't been totally clear how the pathway is involved

  • so that's what this team wanted to figure out.

  • One of the best ways to see what something does is to manipulate it.

  • So this team investigated if stimulating those neural pathways

  • in baby birds would implant the memory of a song.

  • Which, I guess makes sense.

  • But is still totally bananas!

  • When the birds were only about a month old, the researchers used a type of genetic

  • engineering to make some of their brain cells activate in response to light.

  • Then, they raised the animals away from adult birds to make sure they weren't

  • getting any singing lessons outside of the experiment.

  • As the animals grew, researchers simulated song-tutoring by shining

  • a type of blue light directly into their brains at different intervals,

  • which excited those neurons-of-interest in the NIf.

  • From the brain's perspective, there wasn't much difference between this

  • and getting an input from an actual bird.

  • So when the test animals reached adulthood, they had a pretty good idea what their

  • song should sound like, even though they'd never imitated a real animal.

  • Admittedly, there were some differences, so the researchers say these implanted

  • memories guide learning, as opposed to being virtual sheet music.

  • But since the goal was to figure out the HVC's job,

  • those results were pretty awesome.

  • And also slightly upsetting.

  • Like, I'm a little worried about memory implantation.

  • And of course, there are more questions to answer here, too.

  • For instance, another experiment in this paper demonstrated that the HVC pathway

  • is necessary when a bird is learning a song, but not afterward.

  • And it's not clear which part of the brain takes over next.

  • Studies like this are great for animal biology,

  • but this type of research could someday apply to humans, too.

  • There's no guarantee that we will someday be shining light on our brains

  • especially considering those two brain regions in finches don't exist in humans.

  • But this work will likely prompt future experiments that show how social interactions

  • help us imitate sounds.

  • And that could be really helpful in places like speech therapy.

  • In other news, scientists recently got their hands on some cool new tech and used it

  • to study human embryos and fetuses.

  • They published their results last week in the journal Development,

  • and what they found was pretty amazing.

  • The team announced the discovery of new muscles present

  • in fetuses that disappear before birth.

  • And they propose this could teach us more about, of all things, our own evolution.

  • Now, scientists have been researching human development for more than

  • a hundred years, so the fact that fetuses have muscles that adults don't isn't new.

  • But this study used a combination of 3-D imaging techniques to show us

  • that process in the highest resolution yet.

  • That helped scientists update our general body of information,

  • but naturally, the team also carried out a huge analysis of the new data.

  • Because like, what else do you do with a mountain of shiny new info?

  • The team was trying to figure out when in development certain muscles

  • form or split off from each other.

  • And in the process, they found entire muscles

  • that form in the hands and feet but disappear before birth.

  • One set of muscles in the hands, called the dorsometacarpales,

  • was especially interesting.

  • According to the paper, it typically shows up by about seven weeks after conception

  • and fuses with other muscles by about thirteen weeks.

  • If it stuck around, the scientists hypothesize it might be involved in the forearm,

  • or it could act like the extra muscles in our thumbs, which give us more dexterity.

  • These guys.

  • But the coolest part isn't necessarily what the muscle would do.

  • The amazing thing is that, while we rarely see this as a separate muscle

  • in adult humans, it does appear in other animals, like lizards.

  • Did you think I was going to say monkeys?

  • No. Lizards!

  • That's another piece of evidence that we once shared

  • a common ancestor with that group.

  • The team suggests this muscle disappeared from our adult, mammalian ancestors

  • around the time we split off from reptiles.

  • So, roughly two hundred and fifty million years ago.

  • And although it isn't clear why it still appears in fetuses, it's really cool that it does.

  • Getting to draw these kinds of evolutionary connections is a big reason

  • these scientists were interested in studying disappearing structures.

  • And with tools like this new hi-def imaging technology at our disposal,

  • it's exciting to imagine what we'll see next.

  • Speaking of new things, I have an exciting announcement!

  • SciShow is produced by Complexly, a video production company that tries to make

  • content to help people understand ourselves, each other, and the universe.

  • And we're about to try a new thing.

  • We're launching our very first pilot season!

  • Which sounds like such a ridiculous idea to me, but we're doing it!

  • From October 15th to the 31st, we're going to debut

  • three new YouTube channels with three episodes each.

  • They're called History Pop, Stories Retold, and Hashed Out,

  • and you can find more about each of them in the links in the description.

  • At the end of October, we're going to see how the world responded to each channel,

  • how we felt about them, and figure out which to keep producing.

  • So we'd love it if you check them out and if you tell us what you think!

  • Again, check out the description to learn more,

  • and we'll have some new shows starting for you next week!

  • [♩OUTRO]

[♩INTRO]

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我們通過改變鳥類的大腦來教它們唱歌|科學秀新聞 (We Taught Birds to Sing by Altering Their Brains | SciShow News)

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    林宜悉 發佈於 2021 年 01 月 14 日
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