Steering a worm with sub-sonic sounds
Optogenetics is a technique that allows researchers to activate neurons to study and manipulate memories and behavior. It’s amazingly effective, but carries the drawback of requiring surgery on the subject, which then has to live with a cable coupled to their brain, which can be cumbersome, to say the least. A new technology, dubbed sonogenetics, may soon offer a wireless alternative relying on sound instead of light.
While optogenetics has been in use with mice and rats, sonogenetics is starting with the simpler brain found in a nematode Caenorhabditis elegans. To get the neurons to respond to the low-intensity ultrasonic sounds in use, microbubbles of gas were needed as mini amplifiers, propagating the sound oscillations through the worm without actually being invasive. The targets of this process were ion channels called TRP-4, which the sound could open up, activating the cell. By manipulating the worms’ genes, new TRP-4 receptors could be added to other cells, essentially building in an on/off switch for the sound to interact with.
Move to the sub-sonic beat
With new receptors in place the nematodes’ motor neurons, the researchers were able to trigger and manipulate the worms’ movement. They are now in the process of scaling up the process to more complex mouse brains, with the hope that this process could someday be used in humans for therapeutic purposes. By shedding the invasive nature of fiber-optic cabling, sonogenetics might someday be a practical way to work with tissues and structures deep in the brain.
Source: Controlling brain cells with sound waves by Salk Institute, Bioengineer.org