(a) Schematic diagram of the experiment setup. (C: computer, HSP: headstage probe, MACA: microelectrode AC amplifer, USTC: ultrasonic transmitter card, SMF: static magnetic field, ME: microelectrode, US: ultrasound, UST: ultrasound transducer, PM-N: permanent magnet-N pole, PM-S: permanent magnet-S pole, R: rat, PI: positive ion, NI: negative ion, LF: Lorenz force, and EC: electric current). (b) The photography of the experiment setup (SA: stereotaxic apparatus, GW: ground wire, RW: reference wire, UC: ultrasonic collimator, and PM: permanent magnet).