Mojiri Zohre, Akhavan Amir, Rouhani Ehsan, Zahabi Sayed Jalal
Department of Electrical and Computer Engineering, Isfahan University of Technology, Isfahan, 84156-83111, Iran.
Heliyon. 2024 Apr 15;10(8):e29482. doi: 10.1016/j.heliyon.2024.e29482. eCollection 2024 Apr 30.
Deep brain stimulation (DBS) is a method for stimulating deep regions of the brain for the treatment of various neurological and psychiatric disorders such as depression, obsessive-compulsive disorder, addiction, and Parkinson's disease. Generally, DBS can be performed using both invasive and non-invasive approaches. Invasive DBS is associated with several problems, including intracranial bleeding, infection, and changes in the position of the electrode tip. Temporal interference (TI) stimulation is a non-invasive technique used to stimulate deep regions of the brain by applying two high-frequency sinusoidal currents with slightly different frequencies.
This paper presents insights into the response of the spiking in the Hodgkin-Huxley (HH) neuron model of the rat somatosensory cortex by changing the parameters carrier frequency, current ratio, and difference frequency of TI stimulation. Furthermore, in order to experimentally evaluate the effect of TI stimulation on the activation of the left motor cortex, an experiment was conducted to measure the motion induced by the balanced and unbalanced TI stimulation. In the experiment, a three-axis accelerometer was attached to the right hand of the animal to determine the position of the hand.
Simulation results of the HH model showed that the frequency of the envelope of the TI stimulation is identical to the fundamental frequency of the neuron spikes. This result was obtained for difference frequencies of 6 Hz and 9 Hz in balanced and unbalanced TI stimulations. Moreover specifically, when the difference frequency is set to zero, the carrier frequency is within the range of 1300-1400 Hz, and the current range is between 140 and 250 μA/cm, the firing rate reached to its highest value. In the experimental result, the maximum range of movement at a difference frequency of Δ = 6 Hz was approximately 1.6 mm and 5.3 mm in the z and y directions respectively.
The results of the spatial spectrum of the rat hand movement were consistent with the spectrum information of the simulation results. Additionally, steering the interfering region to the left motor cortex leads to noticeable contralateral movement of the right hand while no movement was observed in the right hand during the stimulation of the right motor cortex.
This technique of stimulation for the deep regions of the brain is a promising tool to noninvasively treat various neurological and psychiatric disorders such as morphine dependence in addicted rats.
深部脑刺激（DBS）是一种刺激脑深部区域以治疗各种神经和精神疾病的方法，如抑郁症、强迫症、成瘾和帕金森病。一般来说，DBS可通过侵入性和非侵入性方法进行。侵入性DBS存在一些问题，包括颅内出血、感染和电极尖端位置变化。时间干扰（TI）刺激是一种非侵入性技术，通过施加两个频率略有不同的高频正弦电流来刺激脑深部区域。
本文通过改变TI刺激的参数载波频率、电流比和差频，深入研究了大鼠体感皮层霍奇金-赫胥黎（HH）神经元模型中尖峰的响应。此外，为了通过实验评估TI刺激对左侧运动皮层激活的影响，进行了一项实验，测量平衡和不平衡TI刺激引起的运动。在实验中，将三轴加速度计连接到动物的右手以确定手的位置。
HH模型的模拟结果表明，TI刺激包络的频率与神经元尖峰的基频相同。在平衡和不平衡TI刺激中，差频为6Hz和9Hz时均得到了该结果。此外，具体而言，当差频设置为零时，载波频率在1300 - 1400Hz范围内，电流范围在140至250μA/cm之间时，放电率达到最高值。在实验结果中，差频Δ = 6Hz时，最大运动范围在z方向约为1.6mm，在y方向约为5.3mm。
大鼠手部运动的空间频谱结果与模拟结果的频谱信息一致。此外，将干扰区域转向左侧运动皮层会导致右手明显的对侧运动，而在刺激右侧运动皮层时右手未观察到运动。
这种用于脑深部区域的刺激技术是一种有前景的工具，可用于非侵入性治疗各种神经和精神疾病，如成瘾大鼠的吗啡依赖。
