March 18, 2024 • 2hr 0min

Dr. E.J. Chichilnisky: How the Brain Works, Curing Blindness & How to Navigate a Career Path

Huberman Lab

Dr. EJ Chichilnisky is a professor of neurosurgery, ophthalmology and neuroscience at Stanford University. He is one of the world's leading researchers trying to understand how visual perception occurs and applying that knowledge to develop neural prostheses that could restore vision to the blind.

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Key Takeaways

The retina is a thin sheet of neural tissue at the back of the eye that captures light, transforms it into electrical signals, processes those signals, and sends visual information to the brain. It is arguably the best understood piece of the brain.
There are about 20 distinct retinal ganglion cell types, each representing the entire visual scene but extracting different features like edges, color, motion, etc. They are like "Photoshop filters" sending different "movies" of the visual world to the brain.
Dr. Chichilnisky's lab records from hundreds of cells in human retinas from organ donors using a 512-electrode array. This allows them to identify cell types based on their visual response properties and intrinsic electrical properties.
The goal is to use this knowledge of retinal circuitry to develop "smart" prosthetic devices that can restore naturalistic vision to the blind by stimulating different ganglion cell types in the proper spatiotemporal patterns.
The same approach could potentially be used to augment vision, providing novel visual sensations beyond normal human capabilities. It may also provide a foundation for brain-machine interfaces more broadly.
Dr. Chichilnisky believes we have a responsibility as scientists to translate basic research findings into real-world solutions that benefit humanity. The retina is the ideal starting place given our deep understanding of its function.
On a personal level, Dr. Chichilnisky took a wandering path, exploring math, economics, music and dance before finding his calling in neuroscience. He believes in following your intuition to discover work that provides a feeling of "ease."

Introduction

Dr. EJ Chichilnisky is a professor of neurosurgery, ophthalmology and neuroscience at Stanford University. He is one of the world's leading researchers trying to understand how visual perception occurs and applying that knowledge to develop neural prostheses that could restore vision to the blind.

In this episode of the Huberman Lab podcast, Dr. Chichilnisky explains:

How the retina transforms light into electrical signals to initiate vision
The ~20 distinct retinal ganglion cell types and the visual features they encode
Experiments recording from hundreds of cells in human retinas to identify cell types
Engineering "smart" prosthetic devices to restore naturalistic vision by stimulating specific ganglion cell types
Potential for visual augmentation and broader impact on brain-machine interfaces
The importance of translating basic science to real-world solutions
His personal journey and advice on following intuition to find fulfilling work

Host: Andrew Huberman (@hubermanlab)

Topics Discussed

Anatomy and Function of the Retina (6:11)

The retina has 3 main layers:
1. Photoreceptors that capture light and convert it to electrical signals
2. Interneurons that process and extract features from the photoreceptor signals
3. Retinal ganglion cells (RGCs) that send visual information to the brain
About 20 distinct RGC types, each representing the entire visual scene but extracting different features (edges, color, motion, etc.)
RGC types are like "Photoshop filters" or "movies" sending parallel information streams to different targets in the brain
The brain's visual centers then assemble these signals into a coherent percept

Identifying Retinal Ganglion Cell Types (27:46)

Dr. Chichilnisky's lab records from hundreds of RGCs simultaneously in human retinas from organ donors using a 512-electrode array
Cell types are identified based on their responses to visual stimuli (e.g. flickering checkerboard patterns) and their intrinsic electrical properties
About 7 RGC types are well-characterized; newer recordings reveal ~15 more types with unusual visual response profiles that are not yet fully understood
Parsing RGC types is critical for understanding retinal signaling and for developing cell type-specific stimulation strategies to restore vision

Engineering a "Smart" Retinal Prosthesis (51:27)

Current retinal implants provide crude visual percepts by electrically stimulating RGCs, but ignore the retina's intrinsic circuitry
The goal is to develop "smart" implants that stimulate RGCs in naturalistic spatiotemporal patterns, respecting cell type-specific signaling
Device would record RGC activity to identify cell types, calibrate stimulation parameters for each cell, then activate cells based on camera input
Potential to not only restore vision, but augment it beyond normal human capabilities by independently modulating different visual information streams
Could provide a foundation for brain-machine interfaces more broadly by demonstrating how to interact with neural circuitry

Dr. Chichilnisky's Path and Approach to Science (1:34:20)

Studied math as an undergrad, spent years traveling and playing music before starting 3 different PhD programs and ultimately choosing neuroscience
Importance of exploring to find work aligned with one's talents and values; science benefits from diverse backgrounds
Believes we have a responsibility to translate basic research into real-world solutions; the retina is an ideal starting place
Makes decisions based on intuition and a sense of "ease" rather than purely rational deliberation
Practices informal meditation and yoga; tries to "know thyself, be thyself, love thyself"

Conclusion

Dr. EJ Chichilnisky's work demonstrates the immense potential of studying the retina to understand brain function and develop neuroengineering solutions to restore and augment human capabilities. By identifying distinct retinal ganglion cell types and their functional roles, his lab is paving the way for "smart" prosthetic devices that could provide naturalistic vision to the blind and novel sensory experiences to the sighted.

On a personal level, Dr. Chichilnisky's path highlights the value of exploration and following one's intuition to find work that aligns with our unique talents and provides a sense of purpose. As scientists, he believes we have a responsibility to translate basic research findings into real-world applications that benefit humanity.

Overall, this conversation offers a fascinating window into the frontier of visual neuroscience and neuroengineering, while also touching on broader themes of scientific responsibility, personal development, and the cultivation of ease as a guide to fulfilling work.