Kolovou Kouri, K.; Holzapfel, L.; Ferreira Dias, D.; Meixner, L.; Serdijn, W. A.; Giagka, V.

Vagus nerve stimulation (VNS), a well-established application of electrical neuromodulation, has been effective in treating disorders such as epilepsy and depression. Recent neuroscientific advancements have identified further potential in VNS, calling for technical advancements to explore these possibilities. To address this, we developed a neuromodulation platform that can perform both neural activity excitation and inhibition, to further explore spatially and directionally selective stimulation. The platform can be powered wirelessly through ultrasound and includes a charge balancing mechanism to enhance stimulation safety. The platform performs biphasic and monophasic voltage-controlled stimulation, using 6 electrodes for excitation and 2 for inhibition. The pulse width can be varied between 0 and 1500 s, and the pulse repetition rate between 1 Hz and 1 kHz for excitation and 1 kHz to 50 kHz for inhibition. The implemented charge balancing mechanism uses a digital PID controller to reduce the voltage offset at the stimulation site to values as low as 2 mV. The introduced neuromodulation platform provides a versatile experimental tool intended for, but not limited to, VNS in pre-clinical and clinical settings. It is designed using only commercially available components and is easily reproducible, allowing to explore the possibilities of VNS while identifying the necessary components and processes for developing a miniaturized version.