Amplitude modulated transcranial alternating current stimulation (AM-TACS) efficacy evaluation via phosphene induction.
Amplitude modulated transcranial alternating current stimulation (AM-TACS) efficacy evaluation via phosphene induction.
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DOI：
10.1038/s41598-021-01482-1
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发表时间：
2021-11-15
影响因子：
4.6
通讯作者：
Ruhnau P
中科院分区：
文献类型：
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作者：
Thiele C;Zaehle T;Haghikia A;Ruhnau P
调幅经颅交流电刺激（AM-tACS）是一种新颖的电刺激方法，与传统的电刺激方法相比，由于更容易去除刺激伪像，因此可以在刺激过程中记录电生理信号。为了测量AM-tACS的神经调节潜能，我们测试了其诱导光幻视的能力，作为刺激效果的指标。AM-tACS通过双电极装置应用，连接在FpZ和右眼下方。由不同载波（50 Hz, 200 Hz, 1000 Hz）和调制频率（8 Hz, 16 Hz, 28 Hz）组成的AM-tACS波形以最大2 mA的峰对峰刺激强度进行处理。以相同频率的TACS条件作为诱导光幻视的基准。使用50 Hz载波频率的AM-tACS条件能够诱导光幻视，但在调制频率之间的光幻视阈值没有差异。使用200 Hz或1000 Hz载波频率的AM-tACS不诱导光幻视。TACS条件诱导的光幻视与前人的研究一致。AM-tACS条件下的刺激效果与调幅无关，而仅仅依赖于载波频率。一种可能的解释是，AM-tACS需要更高的刺激强度，其振幅调节才能产生神经调节作用。
Amplitude modulated transcranial alternating current stimulation (AM-tACS) is a novel method of electrostimulation which enables the recording of electrophysiological signals during stimulation, thanks to an easier removable stimulation artefact compared to classical electrostimulation methods. To gauge the neuromodulatory potential of AM-tACS, we tested its capacity to induce phosphenes as an indicator of stimulation efficacy. AM-tACS was applied via a two-electrode setup, attached on FpZ and below the right eye. AM-tACS waveforms comprised of different carrier (50 Hz, 200 Hz, 1000 Hz) and modulation frequencies (8 Hz, 16 Hz, 28 Hz) were administered with at maximum 2 mA peak-to-peak stimulation strength. TACS conditions in the same frequencies were used as a benchmark for phosphene induction. AM-tACS conditions using a 50 Hz carrier frequency were able to induce phosphenes, but with no difference in phosphene thresholds between modulation frequencies. AM-tACS using a 200 Hz or 1000 Hz carrier frequency did not induce phosphenes. TACS conditions induced phosphenes in line with previous studies. Stimulation effects of AM-tACS conditions were independent of amplitude modulation and instead relied solely on the carrier frequency. A possible explanation may be that AM-tACS needs higher stimulation intensities for its amplitude modulation to have a neuromodulatory effect.