1. A method of non-invasively stimulating a neural network in a subject brain, the method comprising: injecting the subject with a solution including nanoparticles formed from a multiferroic material; and causing an alternating current magnetic field directed toward the subject to interact with the nanoparticles to induce local electric charge oscillations in the nanoparticles, which oscillations interact with the neural network causing neurons in a region of the oscillations to fire at frequencies similar to a frequency of the oscillation.