Episode 74: Neurogenesis

Episode 74: Neurogenesis

Author: Tom Chivers and Stuart Ritchie May 28, 2025 Duration: 1:06:23
Science Fictions
ScienceTechnology

Can adults still grow new neurons in their brains? You’d think we might know the answer to the question of adult “neurogenesis” after more than half a century of neuroscience research. But it turns out we don’t.

In this episode of The Studies Show, Tom and Stuart look into the suprisingly controversial question of adult neurogenesis. Are you “stuck with” the number of brain cells you had as a child, or can you add to that number by making the right choices as an adult? And does it even matter?

This podcast is brought to you by Works in Progress magazine, which this week has a new article explaining why nuclear power is so expensive (spoiler: it relies on an incorrect scientific model that we’ve discussed in previous podcast episodes: the “linear no threshold” model. For a full explanation, along with articles on a dizzying array of other progress-related topics, take a look at www.worksinprogress.co.

Show notes

* Summary post on the debate by Scott Alexander from 2018

* 2000 PNAS study on the brains of London taxi drivers

* 2021 retrospective review of taxi driver studies

* Study comparing passed vs. failed cabbies on “The Knowledge”

* Study putting together neuroimaging research on when the brain peaks in volume and other measures

* 1962 Science study on neurogenesis in rats

* 1999 BrdU study in macaque monkeys

* Famous 1998 study on neurogenesis in the human hippocampus

* 2006 PNAS sudy on testing neocortical neurogenesis using Carbon-14 dating

* 2013 study using similar methods on the hippocampus

* 2018 Nature paper claiming no adult neurogenesis

* Associated commentary article

* Atlantic article describing the controversy by Ed Yong

* 2018 paper finding neurogenesis occuring up to age 79

* 2019 Nature Medicine paper claiming “abundant” adult neurogenesis

* Fair-minded 2019 review paper

* Somewhat angrier 2021 review paper

Credits

The Studies Show is produced by Julian Mayers at Yada Yada Productions. We’re grateful to Claire Wang for her help with researching this episode.



This is a public episode. If you'd like to discuss this with other subscribers or get access to bonus episodes, visit sciencefictionspod.substack.com/subscribe

Every week, Tom Chivers and Stuart Ritchie pull apart the biggest arguments and most confusing claims making headlines. Science Fictions isn't just about celebrating breakthroughs; it's a necessary dive into the messy, contested, and often surprising realities of how science actually works. You'll hear them unpack heated debates, examine questionable studies, and explore why even solid research can sometimes lead to public confusion. This podcast serves as a guide through the noise, separating compelling evidence from overblown narratives. Each episode feels like a conversation with two deeply informed friends who aren't afraid to ask tough questions, offering clarity on topics that matter. For anyone curious about the stories behind the science headlines, this is an essential listen. Tune in for thoughtful analysis that goes beyond the press release, grounded in a genuine fascination with how we know what we know.
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