Researchers at Washington University in St. Louis have developed a technique they call sonothermogenetics, which combines ultrasound and genetic modification to achieve non-invasive neural control in deep brain regions. The technique involves using viral vectors to introduce genetic material encoding for ion channels to specific neurons in the brain. An external ultrasound probe can then provide gentle heating, which activates the ion channels, effectively allowing researchers to turn specific neurons on or off. The new approach may eventually lead to effective non-invasive treatments for neurological conditions such as Parkinson’s disease. Techniques that allow researchers to turn neurons on or off have been growing in popularity in recent years, both as a research tool and as a potential mechanism to treat neurological disorders, such as epilepsy or Parkinson’s. One of the most widely reported is optogenetics, in which genetically modified neurons are turned on or off using light. However, this approach typically requires optical fibers to be surgically implanted within the brain. This latest technique can provide deep brain stimulation, but without the need for surgical procedures. It relies on delivering viral vectors to the brain that can target specific neurons. The vectors carry genetic material that codes for thermosensitive ion channels. Once a neuron expresses these channels, it can then be targeted using externally applied ultrasound, which can create heat within a small area of the brain (~1 mm). So far, the research team tested the technique in mice, and delivered the TRPV1 ion channel to specific neurons, while using a head-mounted ultrasound unit to achieve localized heating. “We can move the ultrasound device worn on the head of free-moving mice around to target different locations in the whole brain,” said Yaoheng Yang, a researcher involved in the development of the new technology, in a press release. “Because it is noninvasive, this technique has the potential to be scaled up to large animals and potentially humans in the future.” The technique successfully affected the behavior of treated mice. “Our work provided evidence that sonothermogenetics evokes behavioral responses in freely moving mice while targeting a deep brain site,” said Hong Chen, another researcher involved in the study. “Sonothermogenetics has the potential to transform our approaches for neuroscience research and uncover new methods to understand and treat human brain disorders.” See a video about the technique below: Source
