Theoretical Neuroscience Podcast

On low-dimensional manifolds in motor cortex - with Sara Solla - #36

4 snips
Jan 3, 2026
Sara Solla, a theoretical neuroscientist with a physics background, shares her journey from neural networks to pioneering manifold analyses of motor cortex activity. She explains how modern multi-electrode technology allows for population-level insights, revealing low-dimensional structures in motor tasks. Solla discusses the implications of these findings for brain-machine interfaces and how structured sensory inputs contribute to low-dimensional coding. Her experiences at Bell Labs and collaborations with notable figures add depth to the conversation, making complex concepts accessible.
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INSIGHT

Low-Dimensional Manifolds Describe Motor Cortex

  • Motor cortex population activity often lies on a low-dimensional manifold, sometimes as small as three dimensions.
  • These latent variables capture coordinated patterns across many neurons and simplify comparing sessions and subjects.
ANECDOTE

Hopfield Talk Sparked A Career Shift

  • A John Hopfield talk at a physics meeting inspired Sara Solla to switch toward neural networks research.
  • That led her to IBM and to work on simulated annealing and networks at Bell Labs.
ANECDOTE

Origins Of 'Optimal Brain Damage' Pruning

  • Sara Solla, Jan LeCun and John Denker developed the Optimal Brain Damage pruning idea in 1989.
  • The method prunes weights by saliency (second derivative times weight squared) and became influential decades later.
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