AILSA CHANG, HOST:
Next, an update on using mild pulses of electricity to relieve the symptoms of depression. NPR's Jon Hamilton reports on a new study showing that these pulses can help if they reach the right brain circuit.
JON HAMILTON, BYLINE: Scientists used to think depression was caused by a chemical imbalance in the brain, but Dr. Vikram Rao of the University of California, San Francisco says that idea is outdated.
VIKRAM RAO: A more sort of modern conception is thinking of depression as a circuit dysfunction, meaning that there's something about the way cells in the brain are talking to each other that is not quite right.
HAMILTON: So researchers have been trying to identify those faulty circuits and make them work better. One approach is called deep brain stimulation which delivers pulses of electricity to a specific area in the brain. Kristin Sellers, a postdoctoral researcher who works with Rao, says the trick is to stimulate an area that has a really good connection to the malfunctioning circuit.
KRISTIN SELLERS: The way that I like to think about it is we're trying to get onto a highway, and there's a lot of different on-ramps.
HAMILTON: To find the right on-ramp, Sellers, Rao and a team of researchers studied 25 people with severe epilepsy. These people were in the hospital awaiting surgery and had wires inserted into their brains to help doctors locate the source of their seizures. Many of them also had symptoms associated with depression. The researchers used the implanted wires to stimulate different areas in the brain. And Sellers says they got an immediate response when they stimulated an area called the lateral orbitofrontal cortex or OFC.
SELLERS: What we found was that, consistently, stimulation in the lateral OFC was improving mood in symptomatic patients.
HAMILTON: And as researchers increased the stimulation, the effect on mood became more pronounced. Sellers says one woman in the study described the change as it happened.
SELLERS: She said something to the extent of, wow, I feel a lot better; what did you guys do?
HAMILTON: The OFC is located behind the forehead and above the eyes. And Seller's colleague Vikram Rao says it offers an ideal on-ramp to the brain networks involved in depression.
RAO: It does seem to be a crossroads for connecting many different brain regions that have been implicated in regulating our mood.
HAMILTON: Rao says stimulating this area seems to make circuits work better, if they are faulty to begin with.
RAO: Only the people who had symptoms to start with improved their mood, which suggests that perhaps the effect of what we're doing is to normalize activity that starts off abnormal as opposed to nonspecifically elevating mood.
HAMILTON: The new study, which appears in the journal Current Biology, is just the latest to suggest that deep brain stimulation can help relieve depression.
HELEN MAYBERG: This is another piece in a very complicated puzzle.
HAMILTON: Dr. Helen Mayberg helped pioneer the use of deep brain stimulation for depression more than a decade ago. Now she directs the Center for Advanced Circuit Therapeutics at the Mount Sinai Health System in New York. Mayberg says the new study offers strong evidence that stimulating the OFC can improve the mood of a person who is feeling depressed, but it doesn't show whether the effect is lasting. And she says it doesn't answer an important question.
MAYBERG: What happens if you did this in people who actually have failed every kind of treatment for a major depressive episode and are chronically and intractably ill?
HAMILTON: Mayberg says she's been able to help about 80 percent of these patients by stimulating a different area of the brain, one that happens to share many connections with the OFC. Jon Hamilton, NPR News.
NPR transcripts are created on a rush deadline by Verb8tm, Inc., an NPR contractor, and produced using a proprietary transcription process developed with NPR. This text may not be in its final form and may be updated or revised in the future. Accuracy and availability may vary. The authoritative record of NPR’s programming is the audio record.