Non-invasive brain tissue stimulation with a magnetic coil provides several irreplaceable advantages over that with an implanted electrode, in altering neural activities under pathological situations. We reviewed clinical cases that utilized time-varying magnetic fields for the treatment of epilepsy, and the safety issues related to this practice. Animal models have been developed to foster understanding of the cellular/molecular mechanisms underlying magnetic control of epileptic activity. These mechanisms include (but are not limited to) (1) direct membrane polarization by the magnetic field, (2) depolarization blockade by the deactivation of ion channels, (3) alteration in synaptic transmission, and (4) interruption of ephaptic interaction and cellular synchronization. Clinical translation of this technology could be improved through the advancement of magnetic design, optimization of stimulation protocols, and evaluation of the long-term safety. Cellular and molecular studies focusing on the mechanisms of magnetic stimulation are of great value in facilitating this translation.
Keywords: 4-AP, 4-aminopyridine; Animal models; CD50, convulsant dose; Cellular mechanisms; DBS, deep brain stimulation; EEG, electroencephalography; ELF-MF, extremely low frequency magnetic fields; EcoG, electrocorticography; Epilepsy; GABA, gamma-aminobutyric acid; HFS, high frequency stimulation; KA, kainic acid; LD50, lethal dose; LTD, long-term depression; LTP, long-term potential; MEG, magnetoencephalography; MRI, magnetic resonance imaging; Magnetic stimulation; NMDAR, N-methyl-d-aspartate receptor; PTZ, pentylenetetrazol; REM, rapid eye movement; SMF, static magnetic field; TES, transcranial electrical stimulation; TLE, temporal lobe epilepsy; TMS, transcranial magnetic stimulation; rTMS, repetitive transcranial magnetic stimulation; tDCS, transcranial direct-current stimulation.