Study on the Effectiveness of Focused Microwave Stimulation in Improving Motor Dysfunction in Stroke Rats

This paper presents a non-invasive microwave brain stimulation system for improving motor function after a stroke. The system uses a small circular antenna to generate 6.0 GHz focused pulsed signals, effectively stimulating rat brains. Unlike traditional methods using DC or AC, this system employs centimeter-wave microwaves for non-invasive, precise stimulation. It uses a frequency synthesizer chip with a voltage-controlled oscillator (VCO) for stable signal generation. The circular design enhances the main lobe energy, reduces side lobe energy, and focuses microwave energy on the central unit. We tested the system with a 5 dBm power, 1 Hz pulse, and 50% duty cycle on rats for 20 minutes. The local field potentials (LFPs) from the primary and secondary motor cortices (M1, M2 regions) showed an increased power spectrum. Brain temperature was monitored during stimulation. A 14-day behavioral study confirmed the method's safety and effectiveness, showing improved motor function in stroke-affected rats. This study demonstrates that non-thermal microwave radiation can positively affect brain neurons.