The one hundred billion neurons of the human brain are powered by blood sugar and shoot electrical signals at each other.
Your ups and downs, joys and fears, hunger and sleep are made from cell networks communicating electrochemically.
More than one scientist or doctor has had the idea that changing the electrical states of the brain could produce improved clinical outcomes for depression, anxiety or schizoaffective disorder. Combined with state of the art surgical technique, doctors can now directly apply current to the brain, and some patients respond very well.
If your depression is not being helped by therapy or drugs or other remedies, would electrically stimulating the brain help? The answer is a definite maybe. There is some recent evidence that suggests this leading-edge technique may be a life saver for those resistant to other remedies.
However, the procedures are expensive and involve major surgery, and there is no definitive evidence most people coping with depression would benefit.
Why would changing the electrical state of the brain change emotions?
Neuroscientists have been engaged in basic research and developing theories to explain how disordered communication between various brain regions play roles in diseases such as depression, anxiety and schizophrenia.
Neurobiologists know a fair amount about how the brain works at this point. The basic idea is that the brain's cells are in dense, forest-like networks where they send electrical impulses to each other, as well as secrete and receive hormones and neurotransmitters.
The billions of neurons constantly absorb chemical inputs and in turn they produce electrical pulses. The networks these cells form amplify and dampen the electrical signals coming from other networks. In a similar fashion, signals coming from the nerves on your skin or in your internal organs get gated, filtered and processed by a series of nodes in the brain.
Different networks in the brain are specialized to handle different aspects of our senses, motor functions, thinking and unconscious processes. Many psychiatric and behavioral disorders involve areas becoming less active or more active compared to healthy people.
Unlike a computer, the whole brain, not just a discrete part, is active while people go about their lives. While scientists associate rationality, planning, memory and attention more with the outer surface of the brain, emotions seem to be handled especially by relatively deep and evolutionarily ancient regions. Some of these emotional-brain regions become too active or not active enough during emotional and psychological disorders.
Interestingly, while one might intuitively expect the brain of a depressed person to be dampened or less active overall, there are particular regions that become more active when a person is depressed.
The role of the cingulum in depression, and deep brain stimulation as a potential cure
Many ideas in neuroscience are not of particular use at this time for treating a disease. Clinicians keep up with advances in laboratory research to a degree, but mostly are focused on developing treatment plans for the patients using current therapies.
Nonetheless a number of developments in recent years have gotten the attention of clinicians who treat patients with serious depression that otherwise resists remedy. Of particular interest is the possibility that overactivity in a deep-brain region known as the subcallosal cingulate is occuring in some depressed patients, and that dampening the electrical output of this area would reduce the depression.
The subcallosal cingulate, also called Area 25 by neurologists, is part of the cingulum, a bundle of nerve tracts that enable communication between different parts of the brain. Area 25 seems to be heavily connected to parts of the brain involved in motivation, pleasure, sleeping, and other functions.
Helen S. Mayberg, M.D and colleagues have applied a technique known as deep brain stimulation to the subcallosal cingulate/Area 25. Deep brain stimulation has been used for Parkinson's disease but it's use for depression is comparatively novel.
By using surgery to open the skull and then applying voltage to a specific population of cells, the electrical signals called "action potentials" by scientists are changed in areas of the brain associated with processing of emotion.
Some patients who did not benefit from drugs, therapy or other remedies can experience a noticeable lessening of depression. One patient told the New York Times that " "It was literally like a switch being turned on that had been held down for years," leading to the Times coming up with the phrase "depression switch".
While this idea is likely simplistic, the impressive results of some of the patients treated with the technique may represent a new era in our understanding of depression.
In a February 2012 publication in the Archives of General Psychiatry, Mayberg and colleagues administered deep brain stimulation to the subcallosal cingulate area of 10 patients with major depressive disorder. They report that "a significant decrease in depression and increase in function were associated with chronic stimulation." While there were very few subjects in the study, and additional studies would be needed to make stronger claims, these data are nonetheless promising.
Conclusion
Overall, there is evidence that deep brain stimulation to the subcallosal cingulate works to help patients with depression. Much remains to be discovered about the neurological aspects of depression, and why some patients are not helped by drugs or therapy, but current data is consistent with the notion that medical science has indeed identified a brain region of critical importance.
Deep brain stimulation involves serious surgical procedures and a removal of small portions of the skull to expose the brain. It is a very expensive technique with potential for brain injury, so people with depression should not anticipate it developing into an easy cure anytime soon.
It will take years to determine whether these data can be replicated and whether this currently leading-edge therapeutic technique becomes widely beneficial. Many seemingly-promising therapies that show impressive results with a small cohort early on turn out to be a remedy that is at best only marginally effective for larger numbers.
However, persons who have tried a number of other therapeutic interventions to no avail can only be encouraged by the work of Mayberg and her colleagues. Not only is a new option for treating this condition becoming available, the promising results may give scientists and doctors crucial insights into the biological basis of depression.
