Magnetic Brain Stimulation Rewires the Brain to Treat Depression
On Star Trek, Dr. Leonard McCoy used a "neural stimulator," a small instrument that was used to stimulate specific areas of the humanoid brain. It not only was able to change targeted neural connections through direct contact, but could be operated with a remote control. Although we are still a long way off from the convenience of the compact and remote-controlled neural stimulator, a new study indicates that transcranial magnetic stimulation (TMS) is similar to the Star Trek technology in the sense that it treats depression by stimulating specific areas of the brain.
TMS, a less invasive alternative to electroconvulsive therapy, is a widely accepted treatment for major depression. Instead of applying electric currents directly to the brain, TMS applies a magnetic field to the cranium, which then induces weak electric currents in the brain. But like ECT, the mechanism by which it actually treats depression has been elusive. Previous studies have indicated that the treatment works by changing the interactions between two major neuronal networks in the brain, but none were conclusive. Now, this new study shows that TMS only modulates the connectivity in one of the networks, so it effectively "selectively rewires" the brain.
From the paper: "Before treatment, functional connectivity in depressed patients was abnormally elevated within the DMN (default mode network) and diminished within the CEN (central executive network), and connectivity between these two networks was altered. Transcranial magnetic stimulation selectively modulates functional connectivity both within and between the CEN and DMN, and modulation of subgenual cingulate connectivity may play an important mechanistic role in alleviating depression."
The findings will appear in the October 1 issue of Biological Psychiatry. Editor Dr. John Krystal said of the study, "We are a long way from Star Trek, but even the current ability to link brain stimulation treatments for depression to the activity of particular brain circuits strikes me as incredible progress."
This study not only brings us closer to Star Trek-level targeted brain stimulation, but may also help tailor depression treatments to the individual sufferer. Co-author Marc Dubin said, "Our findings may inform future efforts to develop personalized strategies for treating depression with TMS based on the connectivity of an individual's default mode network. Further, they may help triage to TMS only those patients most likely to respond."