Scientists can now “see” moods inside the brain

Researchers at Baylor College of Medicine developed what they call a “mood decoder” during a small clinical trial of deep brain stimulation as a therapy for treatment-resistant depression.

Using brain scans from the skull, the researchers were able to determine how activity in specific brain regions matched mood, with the hope of being able to objectively measure the severity of depression symptoms as well as identify the best sites to stimulate for therapy.

Although limited to just three patients, the results so far have shown promise, BCM neurosurgeon and trial leader Sameer Sheth told MIT Technology Review’s Jessica Hamzelu. The team was able to identify mood based on specific brain activity – and found a way to stimulate positive mood.

“This is the first demonstration of successful and consistent decoding of human mood in these brain regions,” Sheth told Hamzelu.

Researchers developed what they call a “mood decoder” during a small clinical trial of deep brain stimulation as a therapy for treatment-resistant depression.

Knowing the Enemy: Major depressive disorder “has enormous social and economic consequences,” the authors note in their study, available as a preprint and presented at the annual meeting of the Society for Neuroscience last November.

Almost a third of patients are resistant to treatment, meaning that typical first-line drugs do not work for them. Researchers are constantly looking to other treatments—including psychedelics like psilocybin and ketamine, as well as non-pharmaceutical interventions like deep brain stimulation and even electroconvulsive therapy—but they often face the brain’s biggest barrier: a lack of bodily understanding.

Also Read :  From Panic Attacks At School To Running An LGBTQ Start-Up

“One critical knowledge gap that drives the challenge of treating treatment-resistant depression (TRD) is the lack of understanding of its neurophysiological basis,” the authors wrote.

Simply put: we don’t know how depression works in the brain, as you would, say, a tumor or a prion disease. We cannot see or measure it, beyond how patients describe their experience.

There is an entire field of science—computational psychiatry—dedicated to figuring this out; to put, essential, objective data about the feelings. And while some teams are looking for insights into the brain for neurotransmitters, many efforts are non-invasive, relying on tools like EEG, fMRI and OPM. All of these devices use sensors to make measurements of things going on in the brain outside of it.

As such, they do not yet have precise, physical information.

“This understanding, drilled down to the individual level, will be essential for treatment-resistant patients being considered for invasive neuromodulation such as deep brain stimulation,” the authors wrote.

Also Read :  Campaign highlights effects of teen vaping on mental health

But intracranial measurements—commonly used to monitor seizures—can provide that information.

Mood Decoding, DBS Delivery: “John” was one of the patients in the trial. To help develop deep brain stimulation (DBS) therapy, where precise shocks to specific brain regions could help alleviate his depression, the team used their “mood decoder” to guide the treatment, it reported Hamzelu.

After being implanted with 14 electrodes – 10 sensors to measure brain activity and four to deliver DBS – John remained in hospital for nine days while researchers measured how his brain activity and mood matched.

The team was able to determine how certain brain activity correlated with mood and depression symptoms.

After the monitoring period ended, the team removed the 10 monitoring electrodes, leaving four for John’s DBS treatment, which consisted of targeted electrical pulses to precise areas of his brain. Treatment for depression “saved his life,” he told Hamzelu.

Two other patients also had their brain measurements analyzed. Data in hand, the team was able to determine how specific brain activity correlated with mood and depression symptoms, across “significant variation in depression severity,” the authors wrote in their preprint.

The decoder was very good at predicting patients’ true mood based on their measured brain activity, both for each patient and when their data was combined.


The big picture: Despite evidence of efficacy in these patients, previous trials using DBS for treatment-resistant depression have shown mixed results, with two large clinical trials considered disappointing enough to be dismissed early, Hamzelu reported.

Although the reasons for this are not clear—as is common when working with the brain—it may be based in part on how DBS is delivered.

“We don’t know how to intelligently deliver DBS to any individual,” Sheth told Hamzelu. “This is just very immature therapy.”

A mood decoder may enable a better designed DBS.

However, there are several important caveats to the research. One of them is its size; only the information of three patients was analyzed. The other is with the mood decoder itself. As it is, it would not be a practical way to screen millions of depression sufferers because it is invasive, expensive and carries risk.

Instead, Sheth told Hamzelu, the team hopes for generalizable insights that could potentially be applied more broadly, potentially with less invasive tools to measure the brain.

We would love to hear from you! If you have a comment about this article or if you have a tip for a future Freethink story, please email us at [email protected]


Leave a Reply

Your email address will not be published.