Magnetism is the new magic being used by scientists at the University of Buffalo to activate tiny groups of cells in the brain. The technique, called magneto-thermal stimulation, has been used to induce body movements in mice like running, rotating and losing control of one’s extremities — none of which are an end in themselves, but all of which demonstrate that magnetism can turn on specific cells allowing scientists to study how each of the cells affect a physical response. It’s sort of like tapping on your knee with a hammer to test your reflexes, only now we can actually observe triggers in the brain in a noninvasive way. The magnetic nanoparticles are heated by an external magnetic field which causes neurons’ temperature-sensitive ion channels to open and ions to flow through. The scientists believe the technique may help them treat disorders like depression and epilepsy directly through brain stimulation. The method developed in this research allows researchers to target a very small group of cells measuring only 100 micrometers across – about the width of a human hair. In future, the technique will help scientists to one day map the brain’s entire network of neuronal circuits that control behavior and emotions and develop far better therapies when the brain malfunctions or is injured.