Scientists Used Sound to Control Worm's Brain Cells

Posted on September 16, 2015

Scientists have used sound waves to control a worm's brain cells for the first time. Researchers from the Salk Institute for Biological Studies call the technique sonogenetics. In the experiments the researchers were able to selectively and noninvasively turn on groups of neurons inside the brain of a worm and control the worm's movement.

The researchers used sound waves on the brain of the nematode Caenorhabditis elegans. Microbubbles of gas were used to amplify the low-intensity ultrasound waves. These bubbles grown and shrink in tune with the ultrasound pressure waves and can be made to propagate into the worm brain. The researchers used a membrane ion channel, called TRP-4, which can respond to the waves. The worm changes direction in response to the ultrasound pulse in this video:

Sreekanth Chalasani, an assistant professor in Salk's Molecular Neurobiology Laboratory and senior author of the study, says in a statement, "Light-based techniques are great for some uses and I think we're going to continue to see developments on that front. But this is a new, additional tool to manipulate neurons and other cells in the body."

The researchers say the sonogenetics technology could be used on any calcium-sensitive cell type in any organism including humans. The researchers have also started testing the technology on mice.

Chalasani says, "“The real prize will be to see whether this could work in a mammalian brain. When we make the leap into therapies for humans, I think we have a better shot with noninvasive sonogenetics approaches than with optogenetics."

Other scientists say reproducing the technology in mammals will not be as easy. Michael Hausser, a professor of neuroscience at University College London, told BBC News, "The important thing to remember here is that the worm is only 1mm long... with the neurons only 25 micrometres beneath the surface: a quarter of the diameter of a human hair. This makes it an ideal organism for ultrasound to influence neural activity. It will be a much greater challenge to get such a technique to work in a big brain within a skull."

A research paper on the study was published in the journal Nature Communications.

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