Given the widespread legalization of cannabis for medical and recreational uses, you'd think we'd have a better understanding of how it works. But ask a neuroscientist exactly how cannabinoid compounds like THC and CBD alter our perceptions or lead to potential medical benefits, and you'll soon learn just how little we know.

We know that these molecules hijack an ancient signaling system in the brain called the "endocannabinoid" system (translation: the "cannabinoids within"). These somewhat exotic signaling molecules (made of fatty lipids and traveling "backwards" compared to other transmitters) have been deeply mysterious until recently, when new tools made it possible to visualize their activity directly in the brain.

So what is the "day job" of the endocannabinoid system — and how does it connect to the dramatic highs that come with taking THC or the medical benefits of CBD?

To unpack all this, we're talking this week with neuroscientist Ivan Soltesz, the James Doty Professor of Neurosurgery and Neuroscience at Stanford, and a leading expert on the endocannabinoid system.

Learn More

• The Soltesz Lab
• "Weeding out bad waves: towards selective cannabinoid circuit control in epilepsy" (Soltesz et al, Nature Reviews Neuroscience, 2015)
• "Keep off the grass? Cannabis, cognition and addiction" (Parsons et al, Nature Reviews Neuroscience, 2016)
• "Marijuana-like brain substance calms seizures but increases aftereffects, study finds" (Goldman, Stanford Medicine News, 2021)
• "Retrograde endocannabinoid signaling at inhibitory synapses in vivo" (Dudok et al, Science, 2024)

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Episode Credits

This episode was produced by Michael Osborne at 14th Street Studios, with production assistance by Morgan Honaker. Our logo is by Aimee Garza. The show is hosted by Nicholas Weiler at Stanford's Wu Tsai Neurosciences Institute.

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Thanks for listening! If you're enjoying our show, please take a moment to give us a review on your podcast app of choice and share this episode with your friends. That's how we grow as a show and bring the stories of the frontiers of neuroscience to a wider audience.

Learn more about the Wu Tsai Neurosciences Institute at Stanford and follow us on Twitter, Facebook, and LinkedIn.

Today we are re-releasing an episode we did last year with Stanford neurobiologist Lisa Giocomo exploring the intersection of memory, navigation and the boundaries we create between ourselves and the world around us.

This episode was inspired by the idea of memory palaces. The idea is simple: Take a place you're very familiar with, say the house you grew up in, and place information you want to remember in different locations within that space. When it's time to remember those things, you can mentally walk through that space and retrieve those items.

This ancient technique reveals something very fundamental about how our brains work. It turns out that the same parts of the brain are responsible both for memory and for navigating through the world.

Scientists are learning more and more about these systems and the connections between them, and it's revealing surprising insights about how we build the narrative of our lives, how we turn our environments into an internal model of who we are, and where we fit into the world.

Join us to learn more about the neuroscience of space and memory.

Before we get into this week’s episode, we have a favor to ask. We're working to make this show even better, and we want to hear from you. We're in the process of gathering listener input and feedback. If you'd be willing to help out, send us a short note and we'll be in touch. As always, we are at neuronspodcast@stanford.edu

Learn more:

• About Lisa Giocomo’s research
• About the story of Henry Molaison (patient H. M.), who lost the ability to form new memories after epilepsy treatment removed his hippocampus.
• About the 2014 Nobel Prize in medicine, awarded to John O’Keefe and to May-Britt and Edvard Moser (Giocomo’s mentors) for their discovery of the GPS system of the brain.
• About Memory Palaces, a technique used since ancient times to enhance memory using mental maps.

Episode Credits

This episode was produced by Michael Osborne at 14th Street Studios, with production assistance by Morgan Honaker. Our logo is by Aimee Garza. The show is hosted by Nicholas Weiler at Stanford's Wu Tsai Neurosciences Institute.

Send us a text!

Thanks for listening! If you're enjoying our show, please take a moment to give us a review on your podcast app of choice and share this episode with your friends. That's how we grow as a show and bring the stories of the frontiers of neuroscience to a wider audience.

Learn more about the Wu Tsai Neurosciences Institute at Stanford and follow us on Twitter, Facebook, and LinkedIn.

In the past few years, Big Pharma has released not one, but three new treatments for Alzheimer’s disease.

Aducanemab (2021), Lecanemab (2023), and Donanemab (2024), are the first treatments to effectively clear the brain of amyloid plaques — the sticky protein clumps whose build-up in the brain has defined the disease for decades. The problem? They may not help patients at all.

Today’s guest, Stanford neurologist Mike Greicius, considers the new amyloid-clearing drugs a major disappointment — and worse, says they likely do more harm than good for patients.

Despite this critique, Greicius, thinks that the next few years will be an exciting time for novel Alzheimer’s therapies, as growing biological understanding of Alzheimer’s risk and resilience bear fruit with promising new approaches to treatment.

Learn More:

Greicius is the Iqbal Farrukh and Asad Jamal Professor of Neurology and Neurological Sciences at Stanford Medicine, and a member of the Knight Initiative for Brain Resilience and Alzheimer's Disease Research Center at Stanford University.

Amyloid Drug Skepticism:

• Substantial Doubt Remains about the Efficacy of Anti-Amyloid Antibodies
  (Commentary, Journal of Alzheimer's Disease, 2024)
• New Drug Approved for Early Alzheimer’s (New York Times, 2024)
• Alzheimer's drug adoption in US slowed by doctors' skepticism (Reuters, 2024)
• One step back: Why the new Alzheimer’s plaque-attack drugs don’t work (Stanford Medicine Scope Blog, 2024)

Alzheimer's Genetics Research:

• Knight-funded research uncovers gene mutations that may prevent Alzheimer’s Disease (Knight Initiative for Brain Resilience, 2024)
• Why is a common gene variant bad for your brain? (Stanford Medicine Magazine, 2024)
• Scientists find genetic Alzheimer’s risk factor tied to African ancestry (Stanford Medicine, 2023)

Episode Credits

This episode was produced by Michael Osborne, with production assistance by Morgan Honaker, and hosted by Nicholas Weiler. Art by Aimee Garza.

Send us a text!

Thanks for listening! If you're enjoying our show, please take a moment to give us a review on your podcast app of choice and share this episode with your friends. That's how we grow as a show and bring the stories of the frontiers of neuroscience to a wider audience.

Learn more about the Wu Tsai Neurosciences Institute at Stanford and follow us on Twitter, Facebook, and LinkedIn.