American researchers have developed a new technique for the activation of neurons by ultrasound. Optogenetics is a technique that works the same way that neurons are activated with light, but replacing light with ultrasound. The new technique, called sonogenetics, has been published in the journal Nature Communications.
In optogenetics, a channel of light-sensitive ions is added to the neurons being studied by means of genetic methods, which allows by a laser to turn on or off such neurons. The problem is that light does not pass through the brain well and in order to reach the neurons in depth it is usually necessary to introduce optical fibers by surgery, for example. Low-frequency ultrasound runs through the body smoothly. Therefore, researchers at the Salk Institute and the University of California have been investigating the possibility of controlling neurons even with ultrasound.
A low-frequency ultrasound sensitive ion channel has been found and tested with the nematode Caenorhabditis elegans. First, it ensured that low-frequency ultrasound does not affect these worms themselves. Subsequently, these ion channels have been expressed in some neurons and have shown that these neurons can be activated with ultrasound. For this it is necessary to amplify ultrasound with gas microburbuils.“It will be a real reward to see if this also works in the brain of mammals,” says researcher Sreekanth Chalasani in the press release released by the Salk Institute. They have already started researching in the mouse and have a hope that can be useful also in the human being. “When we make the leap to therapies for humans, I think sonogenetics will be better than optogenetics,” says Chalasani.