A New Multi-mode, High Pressure Portable Transcranial Ultrasound Stimulation System.

Objective: Transcranial ultrasound stimulation (TUS) is a promising non-invasive neuromodulation method for brain disorders. Commonly-used TUS systems in research include custom-built and commercial devices. Custom-built devices typically consist of traditional function generator, power amplifier, and ultrasound transducer. Due to cumbersome wiring and absence of dedicated control software, the operation of these devices is inconvenient. Commercial devices often have limited waveform modes and cannot perform ultrasound modulation with complex waveforms. These limitations limit the application of TUS technology by ordinary users. Therefore, we propose a portable TUS system with multiple modes and high acoustic pressure.

Methods: The proposed portable TUS system utilizes a high-power multi-mode stimulator, and an ultrasound transducer with impedance matching module to achieve multiple modes and high acoustic pressure ultrasound neuromodulation.

Results: The stimulator can output four types of waveforms: continuous pulse continuous stimulus (CPCS), intermittent pulse continuous stimulus (IPCS), continuous pulse intermittent stimulus (CPIS), and intermittent pulse intermittent stimulus (IPIS). When using a same transducer, it generates a peak negative pressure that is nearly identical to one produced by a commercial device. And compared to commercial transducer, the peak negative pressure of our transducer is significantly higher, reaching a maximum of 0.95 MPa.

Conclusion: In-vitro experiments were conducted using rat hippocampal brain slices. The experimental results demonstrated the effectiveness of the TUS system for neural stimulation.

Significance: It offers a design method of a portable multi-mode, high pressure TUS system, which is used for complex neural modulation research.