This radio story tries to cram a lot into five minutes, so if you don't find what you need here, put a comment on the blog, below and I'll see if I can't provide a lead to more information.

Transcranial magnetic stimulation interested me, in part, because of how non-invasive it is. Dr. Bret Schneider, who offers TMS from his private practice in Portola Valley, was one of several experts to suggest that TMS machines might one day be available for home use. Of course, that's a long way off. TMS is expensive: about $5,000 for an initial round of treatment. It's still much easier and cheaper to simply pop a pill each morning. And researchers are still working out how effective it can be.

Studies show that TMS brings a remission in depression to about a third of patients to try it. Another third experience some improvement, and a final third are unaffected. Dr. Schneider says he sees much better success rates on patients who combine TMS with antidepressant drugs (TMS without drugs, he says, is like "trying to drive a car with no gas.") Finally, the FDA approval covers only one TMS machine on the market, Neurostar, although some physicians use other techniques, off-label.

You can find links to the abstracts of clinical studies performed on TMS and depression through a search at pubmed.com. This meta-analysis compares 30 double-blind studies, covering a total of 1164 patients (606 received TMS, 558 received sham treatments).

But TMS is just one in a class of "brain stimulation" depression treatments — an important fact that didn't make it into the story. Others include vagus nerve stimulation, deep brain stimulation and, of course, electroshock convulsive therapy — which is offered here in the Bay Area at the UCSF Langley Porter Psychiatric Institute to severely depressed patients (as well as, less commonly, people suffering from manic depression and schizophrenia).

Quest TV will cover TMS and other depression treatments in greater depth later this season, so stay tuned. For a sneak peak at some of what you'll find on the show, check out Stanford scientist Karl Deisseroth's groundbreaking work using light-sensitive proteins to stimulate neural circuits — work that could someday help treat not just depression, but other brain diseases as well.

Listen to the Depression Advancements radio report online or check out the slideshow below of Dr. Bret Schneider, a consulting assistant professor at Stanford University and a practicing psychiatrist in Portola Valley, discussing depression and the brain.

Being a neurologist in the era of fMRI scanners must feel like being a kid in a candy shop. What's going in there while we're, say, shopping? How about reading? Watching campaign ads? Now that we have a way to take real-time images of the brain at work, the scientific possibilities are endless.

On the surface, the experiment at the heart of this story might seem pretty narrow. It focuses on a rare disorder called pseudobulbar affect, which afflicts only people with ALS, or Lou Gehrig's disease — a far cry from the universal rites of shopping or reading. But what’s fascinating about pseudobulbar is the light it might shed on all of us, and one of the most primal and mysterious human experiences of all: emotion.

People with pseudobulbar get happy and sad, just like the rest of us. They laugh and cry like the rest of us too. But then sometimes, something else happens: They keep going. And going. In this video, you can see how what looks like a laughing fit morphs into something else entirely. It’s as if the laughing and crying mechanisms have become detached from whatever part of the brain triggered the emotion in the first place. Maybe – and this is the hope of scientists Howard Rosen and Robert Levenson – by seeing that disconnect take place in real time through the fMRI, we’ll understand, for the first time, how emotion plays out in people without pseudobulbar affect.

(And it doesn’t stop there. Listen to the radio piece to hear Rosen's theory about what PBA might mean for depression, obsessive compulsive disorder, and, particularly, PTSD.)

Finally, a note about Matt Chaney. As Rosen and Levenson remarked many times, science can't happen without people like Chaney. While the rest of us sat comfortably in front of the fMRI monitors, Chaney spent an hour and a half lying in the cramped quarters of an MRI tube, watching highly emotional videos designed to make him sad. Moving his head by a millimeter would blur the image, so not only is Chaney being taken on an emotional roller coaster, he's doing it without moving a muscle – a lot to ask from anyone, let alone someone with a degenerative muscular disease like ALS.

Journalism is a little less demanding (at least I hope so) but Chaney added to an already long day by spending time in an interview with me. He and his wife, Liz, were also extremely generous in allowing us to share videos of them, which illustrate pseudobulbar far more movingly and effectively than anything I could have written.

Listen to the Decoding the Emotional Brain radio report online, and watch our Web Extra: Emotions from the Inside and Out video.