People suffering from depression have feelings of sadness and/or a loss of interest in activities once enjoyed which may cause a variety of emotional and physical problems and can decrease a person’s ability to function at work and at home. Improvement in mood of people suffering from depression has been observed by stimulation of a brain region called the lateral orbitofrontal cortex (OFC). The OFC is a key hub for mood-related circuitry and is regarded as one of the least well-understood brain regions.
In the new study, the researchers mainly focused on the electrical stimulation on the OFC. Researchers have found an effective target in the brain for electrical stimulation that raises depressed people’s mood. However, those effects were not seen in patients without mood symptoms which proved that the brain stimulation works to normalize activity in mood-related neural circuitry. Vikram Rao, of the University of California, San Francisco, stated that stimulation induced a pattern of activity in brain regions connected to OFC that was similar to patterns seen when patients naturally experienced positive mood states. As a result of the research, OFC is found to be a promising new stimulation target for treatment of mood disorders. Rao and Kristin Sellers with team in the lab of Edward Chang performed their study on 25 patients with epilepsy who had electrodes placed in the brain for medical reasons to pinpoint the origin of their seizures. Many of those patients suffered from depression, which is often seen in people with epilepsy. With the patients' consent, Chang's team used those electrodes to deliver small electrical pulses to areas of the brain thought to be involved in regulating mood. Although OFC is a more superficial target, it has rich interconnections with several brain regions implicated in emotion processing which made this relatively small brain area an attractive target for therapeutic stimulation. The researchers used the implanted electrodes to stimulate OFC and other brain regions while collecting verbal mood reports and questionnaire scores. The findings proved that mood can be immediately improved by electrical stimulation of a relatively small area of brain. The researchers also said that mood disorders are the result of dysfunction in brain circuits and that the changes in brain activity observed after stimulation is similar to those seen in happy people. However, the study is still on going to know whether stimulation of OFC produces durable improvement in mood over longer periods of time. The researchers are expecting to develop a medical device for patients with treatment-resistant mood disorders that can monitor brain activity in OFC and stimulate only when needed to keep that activity within a healthy range. Vikram Rao said "Ultimately, it would be ideal if activity in mood-related brain circuits could be normalized indefinitely without patients needing to do anything".
By: Anuja Arora