Essentials: Psychedelics & Neurostimulation for Brain Rewiring | Dr. Nolan Williams

Welcome to Huberman Lab Essentials. Today we revisit tools for mental and physical health, with a deep dive on depression and where new treatments are headed. I’m excited to talk with Dr. Nolan Williams about brain circuits, TMS, and psychedelics, but first, why depression remains so disabling despite limited tools.

Depression is the leading cause of disability and it worsens other illnesses; it’s now recognized as a cardiac risk factor. We can map a physical brain–heart pathway with TMS, showing the dorsolateral prefrontal cortex influencing deeper regions and the vagus to slow heart rate, which points to circuit-level targets for people in acute psychiatric crisis where standard meds often fail.

So there’s a concrete brain–heart link, not a vague idea. Which brain area are you stimulating?

We target the dorsolateral prefrontal cortex; a magnetic pulse induces current in cortical neurons and propagates to the anterior cingulate, insula, amygdala, then to brainstem nuclei and the vagus, reaching the heart. It’s specific to this control hub, and patients often say that after rapid TMS, therapy finally makes sense—SPEAKER_01 likens it to restoring the coach–player order.

In depression, cingulate-driven conflict signals overpower prefrontal control; TMS retimes that relationship, like exercise for the brain. When people remit midweek in our dense protocol, several later describe unusually present, mindful states—anecdotal but striking.

Before ketamine and psilocybin, how should we think about SSRIs—useful or not?

SSRIs help a subset across depression, OCD, panic, and anxiety, but their delayed benefit argues for plasticity rather than a simple serotonin shortfall. I frame a shift to psychiatry 3.0: from talk therapy and then the chemical-imbalance era to circuit-focused care, where TMS and psychedelics recalibrate networks like the subgenual cingulate–default mode connection, and patients feel recoverable rather than broken.

On psychedelics, people report fresh perspectives on old beliefs. Why would the brain cling to unhelpful rules?

Many patterns are evolutionarily adaptive in danger but maladaptive at home, as with PTSD hyperarousal. Psychedelics and MDMA may open a highly plastic window for revisiting and reconsolidating memories, and I’m pragmatic: if rigorous trials show benefit, we should use them.

MDMA-assisted therapy yields clinically meaningful PTSD reduction for about two thirds of participants, with durability into years for some, while ketamine’s effect often fades after roughly a week and a half unless redosed. For psilocybin in depression, open-label results run about half to two thirds responding, and blinded trials closer to one third.

What’s the psilocybin brain story and why is it relevant to depression?

Imaging shows psychedelics reduce overall activity but alter connectivity, and antidepressant effects line up with a drop in coupling between the subgenual cingulate and the default mode. We see the same shift after our TMS approach, suggesting a convergent mechanism that loosens negative affect from self-referential processing.

Tell me about ibogaine’s clinical use and who is exploring it.

Ibogaine, derived from iboga root in Gabon, induces a prolonged closed-eye life review with strong self- and other-directed empathy; it is not recreational and can last a day or more. We conducted a first-in-human comprehensive study in special operations veterans, with careful cardiac screening due to risk, and early reports suggest marked relief and self-forgiveness around moral injury—promising but suited only for tightly supervised medical settings.

And ayahuasca—use cases and that Brazilian prisoner study?

Ayahuasca combines plants to enable oral DMT via a reversible MAO inhibitor and appears safe in observational work; it’s used as a sacrament in parts of South America. In a Brazilian study, prisoners who received an ayahuasca session had lower return-to-prison rates than controls, raising intriguing questions about how such states shift behavior, though it’s not a call for casual use.

Before we close, walk us through SNT, your accelerated TMS protocol.

Stanford Neuromodulation Therapy reorganizes TMS using spaced-learning principles, compressing a six-week course into five days with hourly sessions and a higher cumulative dose. Across studies, a majority remit within one to five days—often sixty to ninety percent—durability varies from months to years, and the signal is simple and potent: turn on, stay on, and let the prefrontal system remember to stay on, with minimal side effects.

Thank you for a tour through brain circuits, depression subtypes, and how TMS and psychedelics can help people feel well and avoid the depths of suicidal depression. It’s incredible work, and I can’t wait to have you back.