Fresnoza Shane, Christova Monica, Feil Theresa, Gallasch Eugen, Körner Christof, Zimmer Ulrike, Ischebeck Anja
Institute of Psychology, University of Graz, Graz, Austria.
Institute of Physiology, Medical University of Graz, Graz, Austria.
Exp Brain Res. 2018 Oct;236(10):2573-2588. doi: 10.1007/s00221-018-5314-3. Epub 2018 Jun 26.
Transcranial alternating current stimulation (tACS) can modulate brain oscillations, cortical excitability and behaviour. In aging, the decrease in EEG alpha activity (8-12 Hz) in the parieto-occipital and mu rhythm in the motor cortex are correlated with the decline in cognitive and motor functions, respectively. Increasing alpha activity using tACS might therefore improve cognitive and motor function in the elderly. The present study explored the influence of tACS on cortical excitability in young and old healthy adults. We applied tACS at individual alpha peak frequency for 10 min (1.5 mA) to the left motor cortex. Transcranial magnetic stimulation was used to assess the changes in cortical excitability as measured by motor-evoked potentials at rest, before and after stimulation. TACS increased cortical excitability in both groups. However, our results also suggest that the mechanism behind the effects was different, as we observed an increase and decrease in intracortical inhibition in the old group and young group, respectively. Our results indicate that both groups profited similarly from the stimulation. There was no indication that tACS was more effective in conditions of low alpha power, that is, in the elderly.
经颅交流电刺激（tACS）能够调节脑振荡、皮层兴奋性和行为。在衰老过程中，顶枕区脑电图α波活动（8 - 12赫兹）的降低以及运动皮层中μ节律的降低分别与认知和运动功能的衰退相关。因此，使用tACS增加α波活动可能会改善老年人的认知和运动功能。本研究探讨了tACS对年轻和老年健康成年人皮层兴奋性的影响。我们以个体α波峰值频率（1.5毫安）对左侧运动皮层施加tACS 10分钟。在刺激前后，使用经颅磁刺激通过静息状态下的运动诱发电位来评估皮层兴奋性的变化。tACS在两组中均增加了皮层兴奋性。然而，我们的结果还表明，其作用背后的机制有所不同，因为我们分别观察到老年组和年轻组皮层内抑制的增加和减少。我们的结果表明两组从刺激中获得的益处相似。没有迹象表明tACS在低α波功率条件下，即在老年人中更有效。
