The effects of repetitive transcranial magnetic stimulation on neurogenesis

重复经颅磁刺激（rTMS）的治疗效果和最佳刺激条件的基础尚不清楚。我们从大鼠齿状回的神经发生和正常人高频振荡的调节两方面探讨了rTMS的治疗机制。我们的目的是研究rTMS触发海马神经发生的可能性，如果是这样，以神经发生为指标获得最佳的rTMS刺激条件。给大鼠进行真实或假的经颅磁刺激。对于真正的rTMS组，给予rTMS （10 Hz， 150脉冲，120%运动阈值/天）14天，并将两组进行比较。rTMS的效果。利用溴脱氧尿苷（BrdU）免疫组化技术鉴定齿状回的神经发生。将细胞标记为神经元核蛋白（neuronal nuclear protein, NeuN）以鉴定神经元。在慢速rTMS （0.5 Hz， 50次脉冲，80%运动阈值）下，记录7名健康受试者初级感觉区SEPs（体感诱发电位）的HFOs。7名受试者中有6名受试者在rTMS后HFOs的振幅和功率显著增加，而在假性rTMS后无此现象。这些结果表明，慢速rTMS可能直接增加皮质gaba能抑制性中间神经元的活性，并通过这些抑制性中间神经元抑制皮质兴奋性。为了获得最佳刺激条件，需要研究HFOs随其他rTMS条件的变化。

The basis for therapeutic effect and optimum stimulus condition of rTMS (repetitive transcranial magnetic stimulation) is still unknown. We investigated the therapeutic mechanisms of rTMS in the light of neurogeneais in the dentate gyrus of the rats and the modulation of HFOs (high frequency oscillations) in the healthy human subjects.1. We aimed to examine the possibility that rTMS triggers hippocampal neurogenesis, and if so, to obtain optimum rTMS stimulus condition using neurogenesis as an indicator. Rats were given either real or sham rTMS. For the real rTMS group, rTMS was administered (10 Hz, 150 pulses, 120% motor threshold /day) for 14 days and the two groups were compared. The effects of rTMS .on neurogenesis in the dentate gyrus using bromodeoxyuridine (BrdU) immunohistochemistry, which identifies newly generated cells. Cells were labeled for neuronal nuclear protein (NeuN) to identify neurons.2. HFOs of SEPs (somatosensory evoked potentials) in 7 healthy human subjects were recorded before and after the slow rTMS on the primary sensory area (0.5 Hz, 50 pulses, 80% motor threshold). 6 of the 7 subjects showed significant increase of the amplitude and the power of HFOs after rTMS, while no subjects showed after sham rTMS. These results suggest that slow rTMS might directly increase the activity of GABAergic inhibitory interneurons in the cortex and suppress cortical excitability through these inhibitory interneurons. Studies of HFOs changes with other rTMS conditions are needed to obtain the optimum stimulus condition.