352 | Bing Brunton on Connecting the Connectome to the Body
Get the full intelligence
Search transcripts, export clips, track mentions, and explore all topics from “352 | Bing Brunton on Connecting the Connectome to the Body” inside PodZeus.
In this episode of Mindscape, host Sean Carroll engages in a deep conversation with neuroscientist Bing Brunton about the groundbreaking mapping of the fruit fly's connectome—the complete wiring diagram of its nervous system, which includes over 150,000 neurons in the brain and 22,000 in the ventral nerve cord. Brunton explains how this detailed map, once thought to be too complex to interpret, has now enabled her team to simulate and identify a minimal three-neuron circuit (E1, E2, and I1) capable of generating rhythmic motor patterns essential for walking. This discovery, made through computational modeling and iterative pruning of the connectome, demonstrates that even a tiny, specialized neural circuit can produce complex behavior. The discussion extends to the broader implications of 'embodied neuroscience,' arguing that brains evolved not in isolation but in constant interaction with bodies and environments. Brunton advocates for building 'digital twins'—virtual, biomechanically realistic simulations of animals—to study how nervous systems control movement and adapt to injury. She warns against misleading claims from startups that use deep learning to make a worm's connectome control a fly's body, emphasizing that behavioral fidelity does not imply biological fidelity. The episode concludes with reflections on consciousness, suggesting that while artificial intelligence may not require biological details, understanding the embodied nature of nervous systems is crucial for both neuroscience and future therapies for spinal injuries and motor dysfunction.
The fruit fly connectome, with over 170,000 neurons, has been fully mapped and is now being used to simulate and identify the minimal neural circuit (three neurons) responsible for generating rhythmic walking patterns.
Computational modeling of the connectome allows researchers to make testable predictions about neural function—such as the role of a previously unknown neuron—before experimental validation.
The concept of 'embodied neuroscience' emphasizes that brains must be studied in the context of the body and environment they evolved to control, not in isolation.
Digital twins—virtual simulations of animals with realistic biomechanics and nervous systems—offer a powerful new tool for understanding neural control, adaptation, and recovery from injury.
Caution is needed when interpreting AI-driven simulations of biological systems: behavioral similarity does not imply biological accuracy, especially when deep learning masks the underlying mechanisms.
The Brain as an Information Processor and the Challenge of the Connectome
Sean Carroll introduces the central theme: understanding how the brain's wiring diagram—the connectome—relates to behavior and body control. He frames the brain not just as a computational organ but as a physical system composed of cells, molecules, and dynamic interactions, setting the stage for a discussion on how connectivity translates into function.
Defining the Connectome: From C. elegans to the Fruit Fly
Brunton clarifies the concept of the connectome, distinguishing between fine-grained (cell-by-cell) and coarse-grained (area-by-area) versions. She contrasts the 300-neuron C. elegans connectome—long mapped but still poorly understood—with the newly completed fruit fly connectome, which includes over 170,000 neurons and offers a more complex, potentially more interpretable system.
Beyond Wiring: The Role of Cell Identity and Biophysical Properties
The discussion deepens into the limitations of the connectome alone. Brunton emphasizes that neuron identity (e.g., dopamine vs. serotonin cells), biophysical properties, and context-dependent signaling are crucial for understanding function—highlighting that a wiring diagram is only part of the story.
From Connectome to Behavior: Simulating the Fruit Fly's Walking Circuit
“We started with 4,000 cells. I told Sarah, if you get it down to a few dozen, I'd be ecstatic. She went off and did it. The answer was three.”
The Power of Embodied Models: Digital Twins and Virtual Bodies
“The brain does not live in a jar. It always controlled a body and it always controlled a specific body.”
“If you use enough deep learning, you can get a worm brain to control a fly body. It works... This is not biologically meaningful.”
“The brain does not live in a jar. It always controlled a body and it always controlled a specific body.”
“We started with 4,000 cells. I told Sarah, if you get it down to a few dozen, I'd be ecstatic. She went off and did it. The answer was three.”
Host
Guest
Bing Brunton
person
Sean Carroll
person
fruit fly
other
C. elegans
other
ventral nerve cord
other
central pattern generator
other
fruit fly connectome
other
glial cells
other
John Tuthill
person
digital twin
other
AMA | April 2026
Sean Carroll's Mindscape: Science, Society, Philosophy, Culture, Arts, and Ideas • 3h 46m • 4/5/2026
350 | J. Eric Oliver on the Self and How to Know It
Sean Carroll's Mindscape: Science, Society, Philosophy, Culture, Arts, and Ideas • 1h 21m • 4/13/2026
351 | Peter Singer on Maximizing Good for All Sentient Creatures
Sean Carroll's Mindscape: Science, Society, Philosophy, Culture, Arts, and Ideas • 1h 15m • 4/20/2026
Get the full intelligence
Search transcripts, export clips, track mentions, and explore all topics from “352 | Bing Brunton on Connecting the Connectome to the Body” inside PodZeus.
Start discovering podcast insights today
Start with a 7-day trial and explore a growing catalog of popular podcasts. No credit card required.
No credit card required • 7-day trial • Cancel anytime