Visualizing the Ultrasound Focusfor Transcranial Stimulation: A Photoacoustic Microscopy Method Based on Ultrasound-Mediated Tracer Delivery

Ultrasound can non-invasively enhance or inhibit neuronal activity, and has great potential as a precise tool for targeted brain stimulation. Precise visualization of the ultrasound focal region is therefore essential, as it ensures precise target engagement and provides a spatial reference for dissecting underlying mechanisms. However, traditional visualization methods are difficult to apply widely to small animal studies. To this end, this study proposes a method of using low-intensity ultrasound to locally open the blood-brain barrier and release a photoacoustic tracer (melanin) to visualize the ultrasound focus by photoacoustic imaging. An in vivo experiment was carried out, and the results demonstrate that the method can accurately visualize the ultrasound focus, which provides an important means for the precise treatment of brain diseases and the study of targeted ultrasonic brain stimulation.