A specific fiber tract between the prefrontal cortex and the subthalamic nucleus is associated with the best clinical outcomes following deep brain stimulation (DBS) in patients with obsessive-compulsive disorder (OCD), according to a study published in the journal Nature Communications.
“Our analysis shows that optimal results are linked to a very specific nerve bundle,” said researcher Andreas Horn, MD, PhD, of Charité – Universitätsmedizin Berlin in Germany. “Reliable evidence for this link was found across the cohorts of patients examined in Cologne, Grenoble, London, and Madrid.”
Dr. Horn led a group of researchers in studying 50 patients with OCD who received DBS at various centers around the world. Researchers used magnetic resonance imaging before and after electrodes were placed in patients’ brains to identify which surrounding fiber tracts the electrodes were selectively stimulating.
Initially, researchers examined 2 patient cohorts that received DBS to the internal capsule or the subthalamic nucleus. Although the brain structures have a variety of connections to other areas of the brain, a specific tract between the prefrontal cortex and the subthalamic nucleus was identified as a suitable target for stimulation in both groups. Precise electrode localizations allowed researchers to predict treatment outcomes in both groups.
Researchers next replicated their findings in 2 independent cohorts. Finally, a comparison with other studies found they, too, described target areas within the same tract identified in this study.
“Our results do not alter the original target area, they simply helped us to define it more precisely,” explained study first author Ningfei Li. “What this means is that, so far, we have had to steer our boat toward an island which was shrouded in fog. Now, we can make out the island itself and perhaps even the pier, so we can aim for it with greater accuracy."