Cerebral implants hold new potential to combat mood disorders


Brain implants that discharge electrical pulses adapted to a person’s feelings and behavior are being tested in people for the first time.

The Defense Advanced Research Projects Agency, the U.S. military’s research department, has funded two teams that have begun trials on algorithms that can detect mood disorders. These devices can shock the brain back into health without a physician’s interference.

This work was presented last November at the Society for Neuroscience, also known as SfN, meeting in Washington, D.C. The work could potentially be used to remedy serious mental illnesses that withstand current therapies. This approach is known as deep brain stimulation and involves discharging electric impulses to modify neural circuitry. It was previously used to treat movement disorders such as Parkinson’s disease but was less effective against mood disorders.

A Scientific American article titled “Brain Implants for Mood Disorders Tested in People” mentioned that in an earlier study deep brain stimulation had no improvement on 90 chronically depressed individuals after a year of treatment.

There are two teams DARPA has funded, groups at University of California, San Francisco and  at Massachusetts General Hospital, also known as MGH. DARPA supports these two teams, as the teams’ goals are to medicate soldiers and veterans with depression and post-traumatic stress disorder. The article stated that, “Each team hopes to create a system of implanted electrodes to track activity across the brain as they stimulate the organ.”

The DARPA-funded scientists say their work will succeed where others have failed because their implants were made specifically for mood disorders. The groups are performing experiments with people with epilepsy who need to have electrodes implanted in their brains anyway to track seizures.

At the SfN meeting, electrical engineer Omid Sani of the University of Southern California — who works with  professor of Neurological Survey Edward Chang’s team at University of California, San Francisco presented the first map of mood’s encoding in the brain. He and his colleagues worked with six people with epilepsy. They recorded the epileptic people’s brain activity and moods over the course of one to three weeks. Using this data, the researchers developed an algorithm to unravel that person’s fluctuating moods from their brain activity. Distinctive patterns appeared, especially evident in brain regions linked to mood.

The article also added, “Chang and his team are ready to test their closed-loop system in a person as soon as they find an appropriate volunteer.”

MGH wanted to pinpoint brain activity linked to  behaviors evident in multiple disorders, such as trouble with focus and empathy. At the SfN meeting, they presented algorithms they created to trigger the brain when someone cannot focus on an assignment, such as matching images of numbers or determining emotions on faces.

The researchers discovered that discharging electrical pulses to regions of the brain linked with decision-making and emotion boosted the performance of test participants. They pinpointed the brain activity associated with flunking their given task because they were aloof and discovered they could invert it with stimulation. Researchers are now starting to assess algorithms that use distinct patterns of brain action as a catalyst to automatically activate the brain.

Wayne Goodman, a psychiatrist at Baylor College of Medicine, wants this method to achieve what deep brain stimulation does not. He hopes this method is successful because recent algorithms are more individualized and are modeled on physiological signals, instead of a doctor's intelligence.

“You have to do a lot of tuning to get it right,”  Goodman said. The Scientific American article wrote. he “is about to launch a small trial of closed-loop stimulation to treat obsessive-compulsive disorder.”

One setback is that excessive modification of emotions to develop paramount happiness can engulf other feelings.

Scientific American also mentioned, “Other ethical considerations arise from the fact that the algorithms used in closed-loop stimulation can tell the researchers about the person’s mood, beyond what may be visible from behavior or facial expressions.”

“We will have access to activity that encodes their feelings,” says Alik Widge, a neuroengineer and psychiatrist at Harvard University, and engineering director of the MGH team. Similar to Chang’s and Goodman’s teams, Widge’s team is collaborating with neuroethicists to discuss ethical considerations.

Chang cautioned that the stimulation technologies his team created are only a first step toward enhanced treatment for mood disorders.

According to the Scientific American article,  “He predicts that data from trials of brain implants could help researchers to develop noninvasive therapies for mental illnesses that stimulate the brain through the skull.”

“The exciting thing about these technologies is that for the first time we’re going to have a window on the brain where we know what’s happening in the brain when someone relapses,” Chang said.