Current techniques to stimulate regions inside the brain need a permanently implanted wire or an optical fiber. Working in mice, Chen and colleagues introduced heat-sensitive capsaicin receptors into nerve cells and then injected magnetic nanoparticles into specific brain regions. The nanoparticles could be heated by external alternating magnetic fields, which activated the ion channel–expressing neurons. Thus, cellular signaling deep inside the brain can be controlled remotely without permanent implants.
The nanoparticles persisted in the brain for over a month, allowing for chronic stimulation without the need for implants and connectors. Wireless deep brain stimulation of well-defined neuronal populations could facilitate the study of intact brain circuits and the treatment of neurological disorders.
.
Chen R, Romero G, Christiansen MG, Mohr A, Anikeeva P: Wireless magnetothermal deep brain stimulation. Science 347(6229): 1477-1480 (2015).
.
http://www.ncbi.nlm.nih.gov/pubmed/25765068