Precision and  flexible technology to modulate brain

Human brain diseases, such as Parkinson’s disease, involve damage in more than one region of the brain, requiring technology that could precisely and flexibly address all affected regions simultaneously.

Researchers have developed a noninvasive technology combining a holographic acoustic device with genetic engineering that allows them to precisely target affected neurons in the brain, creating the potential to precisely modulate selected cell types in multiple diseased brain regions.

The team created AhSonogenetics, or Airy-beam holographic sonogenetics, a technique that uses a noninvasive wearable ultrasound device to alter genetically selected neurons in the brains of mice. Results of the proof-of-concept study were published in Proceedings of the National Academy of Sciences.

“By enabling precise and flexible cell-type-specific neuromodulation without invasive procedures, AhSonogenetics provides a powerful tool for investigating intact neural circuits and offers promising interventions for neurological disorders,” the senior author said.

Sonogenetics gives researchers a way to precisely control the brains, while airy-beam technology allows researchers to bend or steer the sound waves to generate arbitrary beam patterns inside the brain with a high spatial resolution.

“Airy beam is the technology that can give us precise targeting of a smaller region than conventional technology, the flexibility to steer to the targeted brain regions, and to target multiple brain regions simultaneously,” the lead author said.

The team designed each Airy-beam metasurface individually as the foundation for wearable ultrasound devices that were tailored for different applications and for precise locations in the brain.

The team tested the technique on a mouse model of Parkinson’s disease. With AhSonogenetics, they were able to stimulate two brain regions simultaneously in a single mouse, eliminating the need for multiple implants or interventions. This stimulation alleviated Parkinson’s-related motor deficits in the mouse model, including slow movements, difficulty walking and freezing behaviors.

The team’s Airy-beam device overcomes some of the limits of sonogenetics, including tailoring the design of the device to target specific brain locations, as well as incorporating the flexibility to adjust target locations in a single brain.

The device, which costs roughly $50 to make, can be tailored in size to fit various brain sizes, expanding its potential applications.

“This technology can be used as a research platform to speed neuroscience research because of the capability to flexibly target different brain regions,” the author said. “The affordability and ease of fabrication lower the barriers to the widespread adoption of our proposed devices by the research community for neuromodulation applications.”