I cannot create a summary of this article because the search results provided do not include the article titled "Overlapping currents can tune the deep brain" from Science, Volume 391, Issue 6791, March 2026. The search results contain information about deep brain stimulation (DBS) and brain network mapping from other sources, but not the specific article you have listed. In order to create an accurate and factual summary as per your requirements, I would need to have the content of this particular article available.