Lee Jaehoon, Tang Yongkui, Roy Akash, Esfahani Kianoush Sadeghian, Chang Su-Youne, Kim Eun S
Ming Hsieh Department of Electrical and Computer Engineering, University of Southern California, Los Angeles, CA, United States of America.
Department of Neurologic Surgery and the Department of Physiology and Biomedical Engineering, College of Medicine, Mayo Clinic, Rochester, MN, United States of America.
J Neural Eng. 2025 Jul 4;22(4):046004. doi: 10.1088/1741-2552/ade7ae.
This study aims to investigate the modulatory effects of focused ultrasound (FUS) on neuronal activity at the single-cell level, using whole-cell patch clamp recordings in hippocampal slices.A self-focused acoustic transducer (SFAT) was designed and fabricated on a 127m-thick translucent lead zirconate titanate substrate to allow infrared light transmission for visualizing neurons during patch clamp experiments. The SFAT operates at 18.4 MHz, producing low-intensity FUS with a 46m focal diameter at a depth of 400m. Three types of SFAT-active, FUS-blocking control, and low-electromagnetic interference (EMI) versions-were developed to assess the effects of acoustic stimulation, thermal heating, and EMI. Neuronal responses were recorded across 78 tissue samples from 29 animals using 48 combinations of acoustic parameters, including peak-to-peak voltage, pulse repetition frequency (PRF), and pulse duration.Whole-cell patch clamp recordings from CA1 pyramidal neurons in rat hippocampal slices revealed that FUS induces both inhibitory and excitatory effects on action potential firing, depending on the stimulation parameters. Inhibition was found to be the dominant response, while excitation was mainly attributable to thermal effects. Optimal inhibition was achieved with 60 Vpp (ISAPA = 2.11 W cm), 35 kCycles/pulse (1.90 ms), and 100 Hz PRF, yielding a 60% success rate. Conversely, excitation was observed in 60% of trials using 120 Vpp (ISAPA = 8.44 W cm), 50 kCycles/pulse (2.72 ms), and 20 Hz PRF.This work presents a novel neuromodulation platform that combines high-frequency focused ultrasound with real-time whole-cell patch clamp recording at single-neuron resolution. The results provide direct electrophysiological evidence of parameter-dependent, bidirectional modulation of neuronal activity by FUS, offering new insights into its underlying mechanisms and helping define stimulation protocols for future neurotherapeutic applications.
本研究旨在利用海马切片的全细胞膜片钳记录，在单细胞水平上研究聚焦超声（FUS）对神经元活动的调节作用。在一个127μm厚的半透明锆钛酸铅基底上设计并制造了一个自聚焦声换能器（SFAT），以便在膜片钳实验期间允许红外光透过以可视化神经元。该SFAT工作在18.4MHz，在400μm深度处产生焦距为46μm的低强度FUS。开发了三种类型的SFAT——有源型、FUS阻断控制型和低电磁干扰（EMI）型——以评估声刺激、热加热和EMI的影响。使用包括峰峰值电压、脉冲重复频率（PRF）和脉冲持续时间在内的48种声学参数组合，对来自29只动物的78个组织样本记录神经元反应。大鼠海马切片CA1锥体神经元的全细胞膜片钳记录显示，根据刺激参数，FUS对动作电位发放既有抑制作用又有兴奋作用。发现抑制是主要反应，而兴奋主要归因于热效应。使用60Vpp（ISAPA = 2.11W/cm²）、35k周期/脉冲（1.90ms）和100Hz PRF可实现最佳抑制，成功率为60%。相反，在使用120Vpp（ISAPA = 8.44W/cm²）、50k周期/脉冲（2.72ms）和20Hz PRF的60%的试验中观察到兴奋。这项工作提出了一个新的神经调节平台，该平台将高频聚焦超声与单神经元分辨率的实时全细胞膜片钳记录相结合。结果提供了FUS对神经元活动进行参数依赖性双向调节的直接电生理证据，为其潜在机制提供了新的见解，并有助于为未来的神经治疗应用确定刺激方案。
