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Scientists appear to have caught a glimpse of what sadness looks like in the brain. NPR's Jon Hamilton reports that involves a distinct pattern of communication between brain areas involved in emotion and memory.
JON HAMILTON, BYLINE: There's lots of evidence linking sadness and other emotions to a part of the brain called the amygdala. But a team of researchers wanted to know precisely what the amygdala and other brain areas are doing when someone's mood is shifting. Vikaas Sohal is a psychiatrist at the University of California, San Francisco who was part of the team.
VIKAAS SOHAL: We really wanted to get at, you know, when you're feeling down or when you're feeling happy, you know, what exactly is happening in the brain at those moments?
HAMILTON: You can't get that from brain scans. They're too slow. So the team studied 21 people who were in the hospital to get brain surgery for severe epilepsy. Before the surgery, doctors insert tiny wires into the brain and monitor its electrical activity for up to a week. Sohal says the team hoped those recordings would help answer a basic question.
SOHAL: When patients are sitting there watching TV or talking with their family or just waiting or being anxious, you know, which regions of their brain are talking to each other?
HAMILTON: The patients agreed to keep a running log of their moods. Then the team looked to see whether certain moods were linked to communication within specific networks in the brain. And Sohal says some of them were.
SOHAL: What was really surprising to us was that it was the same network in most of the subjects. So in about two-thirds of the subjects, there was one network which over and over again would tell us whether they were feeling happy or sad.
HAMILTON: That network involved communication between the amygdala, which plays a role in emotion, and the hippocampus, which is critical to memory. The signals between these areas became much more intense at times when people reported feeling sad. Sohal says the finding published in the journal Cell may bring comfort to people with depression.
SOHAL: You know, as a psychiatrist, it's incredibly powerful just to I think be able to say to patients, hey, we actually know there's something happening in your brain when you're feeling more down.
HAMILTON: Josh Gordon, who directs the National Institute of Mental Health, says in one sense, the study merely confirms earlier research on animals.
JOSH GORDON: It's finding a circuit, a piece of the brain that we kind of already knew was involved in mood. That's the less-than-wow part. The wow part is that it's in human beings.
HAMILTON: And he says it provides a detailed map of what's going on in the human brain. Gordon says discoveries like this should eventually help patients with mood disorders.
GORDON: It's really important that we find the circuits underlying mood so that we can learn more about them and treat them with the tools that we're developing that are aimed at circuits.
HAMILTON: Tools like transcranial magnetic stimulation, which might someday be used to alter the specific brain circuit causing a patient's depression. Jon Hamilton, NPR News.
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