Implanting electrodes in the brain could help treat people who are suffering from severe depression, but do not succeed in responding to traditional treatment.
Thomas Schlaepfer, professor of psychiatry and psychotherapy at University Hospital in Bonn, Germany and associate professor of psychiatry and mental health at Johns Hopkins University School of Medicine in Baltimore, and his team are examining the prospects of deep brain stimulation, a therapy used to treat tremors associated with Parkinson's disease, to treat depression.
AdvertisementThe idea behind the study is to rearrange disordered neural activity in the brain in a parallel way to how a person might reboot a computer to terminate a problem.
The system consists of a neurostimulator, a device about the size of a hockey puck that is rooted in the chest wall. Wires attached to the stimulator run under the skin to two electrodes that are put in through small holes in the skull and joined to the bone.
The stimulator, which can be operated by the patient, carries electrical current to the electrodes. Depending on its force and frequency, the current controls brain activity in a specific area.
Because a significant symptom of major depression is anhedonia, the inability to find delight from activities formerly experienced as delightful, Schlaepfer's group concentrated on the brain's reward center, a region called the nucleus accumbens, which responds to stimuli from such things as food, sex, and some drugs.
During their most recent study, the researchers surgically implanted the system into three individuals who experienced major depression and who had not responded to other treatments, including drugs of electroconvulsive therapy.
All the patients reported that they sensed no sensations when the stimulator was turned on. They also reported that they felt no changes in their condition after the stimulator was turned on. Yet all of them almost instinctively began preparing for pleasurable activities.
Focusing on the accumbens region of the brain not only seems right from a theoretical standpoint but also from an experimental point of view because it could be one node in a larger circuit that affects depression, said Helen Mayberg, professor of psychiatry and neurology at Emory University School of Medicine in Atlanta.
But experts claim that focusing on the brain's pleasure centre could also have some unpleasant consequences.
"The nucleus accumbens has been modeled as an area of craving. Could you get habituated to the chronic stimulation? Sometimes side effects are worse than your primary symptoms," the Discovery News quoted Mayberg, as saying.
Still, Mayberg added that an in-depth understanding about how the brain functions will lead to better treatments.
"If there's buy-in scientifically and conceptually to the idea of a circuit and that some nodes are more important than others, the engineers will advance the technology," Mayberg said.