Learn about whether adult neurogenesis can help humans grow new brain cells; the super cool way dolphins learn how to use tools; and how keeping good “zeitgeber hygiene” by sticking to a regular routine can keep you happy and healthy.
Learn about whether adult neurogenesis can help humans grow new brain cells; the super cool way dolphins learn how to use tools; and how keeping good “zeitgeber hygiene” by sticking to a regular routine can keep you happy and healthy.
Can you grow new brain cells as an adult? by Grant Currin
Dolphins use tools — and they learn how from other dolphins by Cameron Duke
To stay happy and healthy, maintain your routines -- aka "zeitgeber hygiene" by Kelsey Donk
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Find episode transcript here: https://curiosity-daily-4e53644e.simplecast.com/episodes/stay-happy-and-healthy-by-maintaining-your-routines-how-dolphins-learn-to-use-tools-and-can-adults-grow-new-brain-cells
CODY: Hi! You’re about to get smarter in just a few minutes with Curiosity Daily from curiosity-dot-com. I’m Cody Gough.
ASHLEY: And I’m Ashley Hamer. Today, you’ll learn about whether you can grow new brain cells as an adult; the super cool way dolphins learn how to use tools; and how sticking to a routine can keep you happy and healthy.
CODY: Let’s satisfy some curiosity.
The brain is made of cells called neurons — about 86 billion of them. And when you’re little, your brain spends its time sprouting those neurons, forming connections between them, and getting rid of the connections that don’t get much use. But is it possible to grow new neurons later, after the brain has developed? After nearly a hundred years of study, neuroscientists still aren’t completely sure. But here’s what we do know.
The growth of new neurons is called neurogenesis, and it’s been a topic of debate since the first modern neuroscientist offered an opinion back in 1928. Santiago Ramón y Cajal [Sahn-tee-AH-go Ruh-MOAN ee kuh-HALL] was already a Nobel laureate when he said no, absolutely not. I mean, seriously. He once wrote, quote, “Everything must die, nothing may be regenerated,” end quote.
And that was the story. For decades.
But starting in the 1960s, a few experiments started turning up evidence that adult neurogenesis might be possible, at least in rats, guinea pigs, and cats. Still, most neuroscientists weren’t on board. Then, almost 30 years later, a breakthrough came, when researchers showed that adult rats were able to grow new neurons. They took stem cells from the brains of adult rats and grew new neurons in Petri dishes. Their work and mountains of studies published since suggest that exercise, diet, and other environmental variables can actually promote neurogenesis. A triumph of modern medicine, right? Well, maybe.
Most neuroscientists these days do believe in adult neurogenesis, at least in certain parts of the brain like the hippocampus, which is involved in memory, and the amygdala, which plays a role in emotion. A 2018 study of cadavers didn’t find any evidence of newly sprouted neurons in the hippocampus of adult brains, and samples taken during brain surgery didn’t either. But researchers behind a 2013 study that used entirely different methods estimated that adults add 700 neurons to the hippocampus every day.
A study published last month [June] offers a different way of thinking about adult neurogenesis that might change how researchers approach the century-old question. They found that adult-born neurons are bigger and grow more slowly than neurons formed in the developing brain. Since adult-born neurons take longer to grow and develop, the researchers think they might keep contributing to brain functioning as we age, even if neurogenesis isn’t happening much or at all late in life.
So while you probably can grow new brain cells as an adult, maybe the best advice is to take care of the ones you’ve got.
Dolphins are smart. I mean, they’re neck and neck with great apes in a mammalian battle of wits. Both species have big brains that help them build complex social structures, demonstrate self-awareness, and even learn human hand signals. And both can use tools. Well believe it or not, a new dolphin discovery shows that they learn those skills in similar ways.
The skill I’m talking about comes from the Indo-pacific bottlenose dolphins in Shark Bay, Western Australia, who’ve developed a unique hunting strategy. First, they chase frightened fish into empty gastropod shells — think big, football-shaped things, like conch shells. Then they shove their beaks into the shells and zip! them up to the surface. After that, it’s “bottoms up!” and the dolphin gets a gulp of tasty fish. Some say it looks like a person finishing off a bag of potato chips. Researchers call this behavior shelling — makes sense.
But shelling isn’t the first example of tool use by these dolphins. That award goes to a behavior called sponging, which is where dolphins use marine sponges as a sort of glove to protect their skin from scrapes while foraging in sharp rocks. A dolphin learns this technique by seeing its mother do it and imitating her. This is called vertical social transmission, and it was believed to be the only way that dolphins learn behaviors.
Great apes learn a lot of skills from their mothers, too, but they also engage in horizontal social transmission. That is, picking up behaviors from their friends. This type of social learning has never been seen in dolphins — until now.
For a study, a team led by behavioral ecologist Sonja Wild of the University of Konstanz in Germany spent a decade watching dolphins interact. (Not a bad gig, I’d say.) Out of more than 5,000 dolphin encounters, they observed shelling 42 times in 19 dolphins. Definitely a rare behavior, but the researchers are sure this is an underestimate. It’s hard to watch all the dolphins all the time! Still, that gave the researchers enough data to perform an analysis to track the spread of this behavior through the dolphins’ social networks. They found evidence that the shelling behavior is spreading through small pods of unrelated dolphins. That means they’re learning to shell from their friends, not from Mom.
It’s another win for big-brained mammals! Whether you’re an ape or a dolphin, you can always get by with a little help from your friends.
Wanna be happier and healthier? Well then, listen up. Back in the pre-pandemic times, you probably had a schedule. Every week, you woke up to go to work or school at the same time, came home at the same time, ate your meals at the same time — hopefully, you even exercised and went to bed at the same time. But if you’re one of the many who’s locked down at home right now, that routine has probably gone out the window. And experts say that if you want to feel healthier, happier, and more energetic, you need a routine.
To explain why, I’m going to teach you a word in German: zeitgeber [ZITE-gay-ber]. The word literally means "time-giver,” and it’s the term scientists use for the things that cue the body’s 24-hour clock, or circadian timing system. That includes things like light exposure, exercise, and mealtimes.
Your body’s internal clock doesn’t just help you go to sleep and wake up on time — it has a hand in almost every process in your body, from mood to digestion to the function of your cardiovascular and nervous systems. That means that a disruption can cause big problems. For example, just think about jet lag. An overseas trip seriously messes with your daily routine, and as a result, it can lead to fatigue, irritability, and even bowel problems.
So experts say it’s a good idea to focus on “zeitgeber hygiene” — that is, on performing our zeitgebers consistently to keep our body’s clocks in check. If we don’t, we’ll feel tired, sick, and crabby.
A recent survey from USC’s Center for the Digital Future found that many of us are maintaining pretty bad zeitgeber hygiene right now. One-third of adults say they miss having a regular routine since the pandemic started.
We’ll all probably feel better if we can work some more structure back into everyday life. It’s not just that you need to set a firm schedule. It’s that you need to care for the zeitgebers your body is missing: regularly scheduled daylight, mealtimes, exercise, and sleep. It doesn’t matter when you schedule these things — just that you do them at a consistent time every day. Try not to deviate from those set times by more than an hour, and you’ll probably start to feel better.
ASHLEY: Let’s review what we learned today to wrap up. Starting with
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CODY: Today’s stories were written by Grant Currin, Cameron Duke, and Kelsey Donk, and edited by Ashley Hamer, who’s the managing editor for Curiosity Daily.
ASHLEY: Today’s episode was produced and edited by Cody Gough.
CODY: Join us again tomorrow to learn something new in just a few minutes.
ASHLEY: And until then, stay curious!