TMS sounds like it should work by sending a signal straight into the part of the brain that’s actually causing the trouble.
It doesn’t, and that’s actually the more interesting part of the story.
The magnetic coil sits against the scalp and reaches a region near the surface of the brain. The part of the brain most tied to depression sits much deeper, well out of reach of any coil.
So how does a treatment aimed at the surface end up changing something buried far below it?

The Coil Can’t Reach the Real Target Directly

TMS delivers magnetic pulses to the dorsolateral prefrontal cortex, usually shortened to the DLPFC, a region near the front of the brain involved in planning, focus, and emotional control. It’s easy to reach because it sits close to the skull.
The subgenual anterior cingulate cortex, or sgACC, is a different story entirely. This is a small structure buried deep in the brain, and it shows up consistently in depression research as overactive in people experiencing depressive symptoms.
Imaging studies have found that as effective treatments work, whether that’s medication, therapy, or deep brain stimulation, activity in the sgACC tends to drop.
The problem is the sgACC sits too deep for a TMS coil to reach on its own. So researchers went looking for a way around that limitation, and what they found is genuinely clever.

The Brain Has Its Own Wiring Between These Two Regions

The DLPFC and the sgACC aren’t isolated from each other. They’re connected through a real, physical network of nerve fibers running between them.
In a lot of people with depression, these two regions are inversely linked. When the DLPFC is underactive, the sgACC tends to run hot, and that combination shows up repeatedly in depression research. Some of the strongest evidence for this connection comes from a study using intracranial EEG recordings directly inside the brains of patients undergoing unrelated neurosurgical procedures. Researchers applied TMS pulses to the DLPFC and recorded, with actual electrodes placed deep in the brain, that the sgACC responded. The signal really did travel from one region to the other.
Newer research has pushed this further using something called connectome modeling, essentially mapping out the actual nerve fiber routes connecting these two areas. That research found the length and quality of this specific pathway helps predict how well a person is likely to respond to TMS treatment, which suggests the wiring between these regions isn’t just a side detail. It’s central to how the whole treatment works.

Related – What Is QEEG Brain Mapping and How Can It Guide Mental Health Treatment?

What Happens at the Level of Individual Brain Cells

Recent research has gone even further, recording from individual neurons deep in the brain while TMS was delivered to the DLPFC.
What researchers found was a genuinely elegant pattern. TMS pulses to the DLPFC triggered a burst of activity in neurons associated with executive control networks, the brain’s planning and regulation systems, while simultaneously suppressing activity in neurons tied to limbic circuits, the deeper emotional processing networks tangled up in mood disorders.

In plain terms, stimulating the surface region seems to turn up the brain’s own regulatory system while turning down the overactive emotional circuitry underneath it. That’s a meaningfully different mechanism than simply zapping a mood center directly. It’s more like strengthening the signal from a control tower that then sends its own instructions downstream.

Why This Explains Some Real World Patterns in Treatment

This deeper mechanism helps explain a few things clinicians have noticed for years.
TMS response isn’t identical from person to person, and one reason may be how strong or how efficient that DLPFC to sgACC pathway actually is in a given brain. Some research has found that a more negative, or more strongly inverse, relationship between the two regions is associated with better treatment outcomes, which lines up with the idea that this specific connection is doing real work during treatment.

It also explains why TMS takes time to show results rather than working instantly. Reshaping activity across an entire connected network, rather than flipping a single switch, is a gradual process. Most treatment courses run several weeks for a reason.

Why This Matters Beyond the Science

None of this changes what TMS actually feels like during a session. It’s still a non-invasive, non-sedating outpatient procedure, and someone can typically drive themselves home or head back to work right after.
What it does change is the story behind why TMS works at all, especially for people who’ve tried medication without success. TMS isn’t attempting to chemically alter the entire brain the way many medications do. It’s aiming at a specific network connection, engaging the brain’s own wiring to influence a deeper structure that’s proven difficult to reach any other way.

For someone who’s tried therapy, tried medication, and still hasn’t found real relief, understanding that TMS works through this specific circuit rather than some vague, general stimulation gives the treatment a much more concrete foundation than it might seem to have at first glance.

What This Looks Like at Shifa Health

TMS is offered here as an FDA approved, evidence based option for depression, PTSD, and anxiety, specifically for people who haven’t found enough relief through medication or therapy alone, or who’ve dealt with side effects that made those options hard to sustain.
If you’ve been searching for an approach that targets the actual brain circuitry involved in mood, rather than another medication trial, TMS may be worth exploring. Shifa Health can walk you through whether you’re a good candidate and what treatment would actually look like for your specific situation. Reach out to schedule a consultation.