For anyone studying neural tissues, it would be amazingly useful if you could pick and choose certain neurons to fire when you want them to, so you can observe the effects. For a very long time, there was simply no way to do this: they’re too small and densely packed, and if you wanted to do this on a living sample? Forget about it.
Then along came optogenetics, which gives you the ability to shine a light on a specially prepared neuron and make it fire. But that requires some prohibitive complexities, like inserting a fiber optic cable just where you need it, and is often difficult to target just the right cells.
Now, researchers at the venerable Salk Institute have figured out a way to use ultrasonic waves to do the same thing—but without undesirably affecting the wrong regions.
“In contrast to light, low-frequency ultrasound can travel through the body without any scattering,” says the study’s senior author, Sreekanth Chalasani.
They identified an ion channel—gates in a neuron’s membrane that can be opened or closed—that could respond to ultrasound as long as there are very tiny bubbles present that mechanically deform the ion channels.
So far, this has only been done in C. elegans nematodes, but suggest that the method could be “broadly applied to manipulate cellular functions in vivo.” Check out the paper here.