Beneficial effects, and possible harm, of exposure to weak pulsed electromagnetic fields (PEMFs) may be mediated by a protein related to one that helps birds migrate, according to a study publishing on October 2 in the open access journal PLOS Biology by Margaret Ahmad of Xavier University in Cincinnati and colleagues. The discovery provides a potential mechanism for the benefits of PEMF-based therapies, used to treat depression and Parkinson’s disease, and may accelerate development of magnetic stimulation for other applications.