Transcranial Magnetic Stimulation (TMS) is a well-studied
noninvasive method that results in focused hyperpolarization or
depolarization of specific brain region neurons through the use
of electromagnetic induction to induce weak electric currents
over selected parts of the brain (Chen et al., 2013). Repetitive TMS
(rTMS) is the application of repeated low or high frequency TMS
pulses to a focal cortical area, therefore capable of modulation
cortical excitability beyond the duration of TMS. Chen and
colleagues (2013) performed a meta-analysis to investigate
the results of the randomized control trials to evaluate the
effectiveness of high and low frequency rTMS for the treatment
of MDD. The authors’ findings suggested that both high and low
frequency rTMS when applied to the left or right dorsolateral
prefrontal cortex were in fact, equally effective in the treatment of
MDD. However, the application of low frequency rTMS selectively
to the right dorsolateral prefrontal cortex resulted in development
of fewer side effects. Further investigations will be needed to
explore the effectiveness of TMS treatment and the safety of low
frequency application to the right dorsolateral prefrontal cortex
rTMS for treating MDD.