Experimental Psychology Lab, Department of Psychology, European Medical School, Cluster of Excellence "Hearing4All", Carl Von Ossietzky University, Ammerländer Heerstr. 114-118, 26129, Oldenburg, Germany.
Neuroimaging Unit, European Medical School, Carl Von Ossietzky University, Oldenburg, Germany.
Sci Rep. 2021 Oct 13;11(1):20357. doi: 10.1038/s41598-021-99749-0.
Transcranial temporal interference stimulation (tTIS) is a novel non-invasive brain stimulation technique for electrical stimulation of neurons at depth. Deep brain regions are generally small in size, making precise targeting a necessity. The variability of electric fields across individual subjects resulting from the same tTIS montages is unknown so far and may be of major concern for precise tTIS targeting. Therefore, the aim of the current study is to investigate the variability of the electric fields due to tTIS across 25 subjects. To this end, the electric fields of different electrode montages consisting of two electrode pairs with different center frequencies were simulated in order to target selected regions-of-interest (ROIs) with tTIS. Moreover, we set out to compare the electric fields of tTIS with the electric fields of conventional tACS. The latter were also based on two electrode pairs, which, however, were driven in phase at a common frequency. Our results showed that the electric field strengths inside the ROIs (left hippocampus, left motor area and thalamus) during tTIS are variable on single subject level. In addition, tTIS stimulates more focally as compared to tACS with much weaker co-stimulation of cortical areas close to the stimulation electrodes. Electric fields inside the ROI were, however, comparable for both methods. Overall, our results emphasize the potential benefits of tTIS for the stimulation of deep targets, over conventional tACS. However, they also indicate a need for individualized stimulation montages to leverage the method to its fullest potential.
经颅颞部干扰刺激（tTIS）是一种新的非侵入性脑刺激技术，用于对深部神经元进行电刺激。深部脑区通常体积较小，因此需要精确的靶向定位。到目前为止，还不知道由于相同的 tTIS 组合而导致个体之间电场的可变性，这可能是精确 tTIS 靶向的主要关注点。因此，本研究的目的是调查 25 名受试者之间由于 tTIS 引起的电场的可变性。为此，模拟了由两个具有不同中心频率的电极对组成的不同电极组合的电场，以便用 tTIS 靶向选定的感兴趣区域（ROI）。此外，我们还着手比较 tTIS 的电场与传统 tACS 的电场。后者也基于两个电极对，但它们在共同频率下相位驱动。我们的结果表明，在单个受试者水平上，tTIS 期间 ROI（左海马体、左运动区和丘脑）内的电场强度是可变的。此外，与 tACS 相比，tTIS 刺激更集中，对靠近刺激电极的皮质区域的共同刺激要弱得多。然而，两种方法的 ROI 内电场是可比的。总的来说，我们的结果强调了 tTIS 在刺激深部靶标方面相对于传统 tACS 的潜在优势。然而，它们也表明需要个体化的刺激组合，以充分发挥该方法的潜力。
