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

The conversation opens with depression in general. The host had heard the guest describe it as perhaps the most debilitating condition worldwide. He also pointed out that, compared with conditions like cancer, there are fairly few tools for treating it, though both the number and the potency of those tools are growing. Note on attribution: the speaker labels in this transcript appear to be swapped. Andrew Huberman introduces himself in a segment labeled with Nolan Williams's name. The clinical and research answers that follow, including the claim to have "dual trained as a neurologist and psychiatrist," are labeled "Andrew Huberman" but clearly come from the guest, Dr. Nolan Williams. This article attributes statements by their content.

Williams states it more strongly: depression is "the most disabling condition worldwide." He describes it as both a risk factor for other illnesses and something that makes other medical and psychiatric illnesses worse. His concrete example is the American Heart Association, which recently added depression as the fourth major risk factor for coronary artery disease. It joins three long-standing ones: hypertension, hyperlipidemia and diabetes.

His lab measures brain-heart connections directly. Using transcranial magnetic stimulation (TMS), they can slow the heart rate and capture that slowing when stimulating over mood regulatory regions. He calls this "a direct probe of that connection." Huberman notes that many people treat the heart-mind relationship as soft biology. Williams frames it as a physical pathway.

Williams explains his clinical focus through his training. Having moved back and forth between neurology and psychiatry, he saw that neurology has many ways to treat acute brain-based problems. Psychiatry has nothing comparable for its highest-acuity cases: people with severe depression who end up in emergency settings and inpatient units. He says the field "really hasn't developed a way of consistently being able to treat that problem," so these patients often get the same standard oral antidepressants they were already taking as outpatients.

Stimulation first reaches the dorsolateral prefrontal cortex, which Williams describes as "kind of the sense of control, kind of governor of the brain." The physics rests on Faraday's law: a magnetic pulse induces an electrical current in electrically conducting tissue. In this case that means brain tissue, not skull, scalp or hair. The result is direct depolarization of cortical neurons at the surface of the dorsolateral prefrontal region.

Imaging during stimulation, Williams says, shows the effect spreading down into the anterior cingulate, the insula and the amygdala. From there the tract runs to the nucleus tractus solitarius and on through the vagus nerve to the heart. He concludes that the heart "very consistently seems to be the end organ of the dorsolateral prefrontal cortex." The finding is regionally specific: stimulating visual or motor cortex does not produce it. He cites his own lab's work and that of Martijn Arns in the Netherlands, and says the connection has been replicated "like four or five times."