They combined the location and connectivity of 461 brain lesions, 101 DBS sites, and 151 TMS sites, and compared patients who developed depression, patients who had improvement in depression, and patients who had no change in mood. Using this approach, they identified a brain circuit that is an effective therapeutic target for both invasive and noninvasive brain stimulation treatments. The study also indicates that brain stimulation outcomes vary not according to the technique used – DBS versus TMS – but according to the circuit that is targeted.
The researchers are now working to refine circuit maps for other neuropsychiatric conditions such as anxiety disorders, post-traumatic stress disorder, mania, hallucinations, and movement disorders. Clinical trials are still necessary to determine whether physicians can relieve patient symptoms by targeting the brain circuits identified through the new approach.
“Now that we have concrete evidence that lesions map to treatment targets, we can design more clinical trials to generate new treatments,” Siddiqi said. “This approach gives us highly rigorous hypotheses about treatment targets. When we don’t know much about the brain circuitry of a particular disorder, our study shows how to find the answer to that question and turn it into new treatment targets.”