Department of Electronic Engineering, Hanyang University, Seoul, Republic of Korea.
Department of Biomedical Engineering, Hanyang University, Seoul, Republic of Korea.
J Neural Eng. 2022 Sep 6;19(5). doi: 10.1088/1741-2552/ac8503.
. Temporal interference stimulation (TIS) has shown the potential as a new method for selective stimulation of deep brain structures in small animal experiments. However, it is challenging to deliver a sufficient temporal interference (TI) current to directly induce an action potential in the deep area of the human brain when electrodes are attached to the scalp because the amount of injection current is generally limited due to safety issues. Thus, we propose a novel method called epidural TIS (eTIS) to address this issue; in this method, the electrodes are attached to the epidural surface under the skull.. We employed finite element method (FEM)-based electric field simulations to demonstrate the feasibility of eTIS. We first optimized the electrode conditions to deliver maximum TI currents to each of the three different targets (anterior hippocampus, subthalamic nucleus, and ventral intermediate nucleus) based on FEM, and compared the stimulation focality between eTIS and transcranial TIS (tTIS). Moreover, we conducted realistic skull-phantom experiments for validating the accuracy of the computational simulation for eTIS.. Our simulation results showed that eTIS has the advantage of avoiding the delivery of TI currents over unwanted neocortical regions compared with tTIS for all three targets. It was shown that the optimized eTIS could induce neural action potentials at each of the three targets when a sufficiently large current equivalent to that for epidural cortical stimulation is injected. Additionally, the simulated results and measured results via the phantom experiments were in good agreement.. We demonstrated the feasibility of eTIS, facilitating more focalized and stronger electrical stimulation of deep brain regions than tTIS, with the relatively less invasive placement of electrodes than conventional deep brain stimulation via computational simulation and realistic skull phantom experiments.
. 时程干扰刺激（TIS）已显示出作为一种新方法的潜力，可用于小动物实验中深部脑结构的选择性刺激。然而，当电极附着在头皮上时，由于安全问题，注入电流的量通常受到限制，因此向人脑深部区域直接施加足够的时程干扰（TI）电流以诱导动作电位具有挑战性。因此，我们提出了一种称为硬膜外 TIS（eTIS）的新方法来解决这个问题；在这种方法中，电极附着在颅骨下的硬膜外表面。. 我们采用基于有限元方法（FEM）的电场模拟来证明 eTIS 的可行性。我们首先根据 FEM 优化了电极条件，以向三个不同目标（前海马体、丘脑底核和腹侧中间核）中的每一个提供最大 TI 电流，并比较了 eTIS 和经颅 TIS（tTIS）之间的刺激聚焦。此外，我们进行了真实颅骨-幻影实验，以验证 eTIS 的计算模拟的准确性。. 我们的模拟结果表明，与 tTIS 相比，eTIS 具有避免将 TI 电流输送到不需要的新皮层区域的优势，对于所有三个目标都是如此。结果表明，当注入足够大的电流（相当于硬膜外皮质刺激的电流）时，优化后的 eTIS 可以在三个目标中的每一个诱导神经动作电位。此外，通过幻影实验进行的模拟结果和测量结果吻合良好。. 我们通过计算模拟和真实颅骨幻影实验证明了 eTIS 的可行性，与 tTIS 相比，eTIS 能够更聚焦、更强地刺激深部脑区，并且电极的放置相对侵入性较小，比传统的深部脑刺激方法更具侵入性。
