Karl Deisseroth: Stanford psychiatrist and bioengineer who pioneered optogenetics (light-controlled neurons via algae channelrhodopsins) and the CLARITY brain-clearing method. Author of the book 'Projections: A Story of Human Emotions.'
What this episode covers
In the inaugural Huberman Lab guest episode, Andrew Huberman interviews Dr. Karl Deisseroth, a practicing psychiatrist and research scientist at Stanford. They explore why psychiatry is uniquely hard, relying only on words and rating scales without blood tests or brain scans to diagnose depression, schizophrenia, autism, and ADHD. Deisseroth explains optogenetics, the technology his lab built to switch specific neurons on and off with light, and how it can reveal the causal circuits behind symptoms so future treatments can be precise rather than serendipitous. They discuss vagus nerve stimulation, electroconvulsive therapy, clozapine, dissociation and ketamine, psychedelics and MDMA for trauma, and the CLARITY method that makes brains transparent. The conversation closes with Deisseroth describing how he manages his clinic, large lab, family of five, and writing through protected, motionless thinking time.
Recommended on this episode
On the Move: A Life (Oliver Sacks autobiography)
Oliver Sacks
“I just finished for the third time, Oliver Sacks' autobiography which is marvelous and I highly recommend to people.”— Andrew Huberman
The guest's own work
Projections: A Story of Human Emotions
Karl Deisseroth
“We also discuss Dr. Deisseroth's newly released book, which is entitled "Projections: A Story of Human Emotions".”— Karl Deisseroth
Also referenced (named, not recommended)
Adderall
Teva
“This is typically Adderall or stimulants of some kind? - Yeah, for example the stimulants, that's right.”— Andrew Huberman
MacBook (Focus mode)
Apple
“there's a focus mode on the MacBook which kind of rules the border, and you just have your documents and it's very pure”— Karl Deisseroth
Neuralink
Neuralink
“What are your thoughts about brain machine interface and Neuralink always comes up, although I do want to point out a tremendous respect for the folks at Neuralink”— Andrew Huberman
Big reveals from this episode
- Channelrhodopsins were recently used to restore light perception to a fully blind human patient for the first time.
- Deisseroth's colleague Botond Roska put channelrhodopsins into a blind patient's eyes and conferred new light sensitivity that wasn't there before.
- Vagus nerve stimulation for depression was chosen largely because the nerve is simply accessible, not because of a precise hypothesis.
- Deisseroth routinely uses a radio-frequency controller in clinic to dial up a patient's vagus nerve stimulation in real time.
- The most effective antipsychotic, clozapine, has terrible side effects yet works when nothing else does.
- His lab mapped the circuit basis of dissociation in both mice and a human epilepsy patient, reproducing the same brain pattern across species.
- Huberman confesses he had a grunting tic as a child and felt mental clarity after head impacts from boxing and skateboarding.
- Deisseroth argues compulsive phone checking can't be diagnosed as a disorder today because it actually aids social and occupational functioning.
Worth remembering
- Psychiatry diagnoses disorders with no blood test or brain scan, using only words and symptom rating scales.
- Antidepressants originally arose as anti-tuberculosis drugs, discovered serendipitously.
- Parkinson's disease commonly causes severe depression, while ALS rarely does, despite both being neurological.
- The optogenetics story traces back to an 1850s-60s Russian botanist, Andrei Famintsyn, studying light-driven algae behavior.
- Early-morning awakening, waking inexplicably earlier and earlier, is a classic early warning sign of oncoming depression.
- Over 70% of people who experience trauma report dissociation, a separation of the sense of self from the body.
- Deisseroth thinks psychedelics lower the threshold for incomplete or wrong brain hypotheses to reach conscious awareness.
- CLARITY builds a clear gel inside brain tissue and washes away fats, making a whole brain transparent while keeping molecules in place.
- Deisseroth wrote his book in a protected midnight-to-2am block and obsessed for days over single words for rhythm.
- Optogenetics lets researchers both remove and reinstate an experience, providing true causality, a form of gain-of-function.