A new brain stimulation technique!

Neurological disorders such as epilepsy and Parkinson’s disease with deep brain stimulation have had some treatment success, but those require surgical device implantation. At Washington University in St. Louis, a multidisciplinary team has developed a new brain stimulation technique that uses focused ultrasound-specific types of neurons in the brain that can be turned on and off. Without a surgical device, implantation can precisely control motor activity.

The team, led by Hong Chen, in the McKelvey School of Engineering and radiation oncology at the School of Medicine assistant professor of biomedical engineering, is the 1st to provide direct evidence showing cell-type-specific, noninvasive activation of neurons in the brain of a mammal. They combined genetic and ultrasound-induced heating effect, which is named sonothermogenetics by them. It is also the 1st work to show by stimulating a specific target deep in the brain; the ultrasound- genetics combination can robustly control behavior.

The result of three years of research, the National Institutes of Health’s BRAIN Initiative partly funded it, was published online in Brain Stimulation on May 11, 2021. In the senior research team, renowned experts in their fields from both the School of Medicine, including Jianmin Cui, and the McKelvey School of Engineering, were there.

“Our work provided evidence that sonothermogenetics evokes behavioral responses in freely moving mice while targeting a deep brain site,” Chen said. “Sonothermogenetics has the potential to transform our approaches for neuroscience research and uncover new methods to understand and treat human brain disorders.”

Chen and the team using a mouse model delivered a viral construct containing TRPV1 ion channels to genetically selected neurons. Via low-intensity focused small ultrasound burst of heat was provided by them to the select neurons in the brain via a wearable device. A few degrees warmer than body temperature, the heat activated the TRPV1 ion channel to turn the neurons on or off, which acted as a switch.

The work builds on research conducted in Jianmin Cui’s (professor of biomedical engineering) lab published in Scientific Reports in 2016. It was found for the 1st time that ultrasound alone can influence ion channel activity and could lead to new and noninvasive ways to control the activity of specific cells.