In optogenetics, specific neurons are modified to produce light sensitive proteins that activate the cell when they are hit with light. The main drawback is that it is hard to get the light deep into the brain. Ultrasound, on the other hand, can reach everywhere — and if it is strong enough — directly activate anything. If there was a way to make ultrasound selective for some neurons, but not others, somebody might get rich.
Enter sonogenetics, 2015’s brand new neuroscience technique of the year. To use it, you simply apply the same bit of genetic engineering you would use to introduce light-sensitive proteins, but instead pop in vibration-sensitive proteins. If you are able do that, a wonderful thing can happen: provided you dial down the ultrasonic power to a nice safe level, a level well below the threshold that would normally get any neuron jumping, you can target just those neurons that you introduced to fancy mechanoreceptors.
The first researchers to completely grasp this promethean power whole in their minds, and actually pull off the technique in the lab, hail from California’s Salk institute and the UCSD. Writing yesterday in the journal Science, they took sonogenetics out for a test drive in the worm. To fully appreciate what the worm can now do for us, try to might imagine what it would be like to be on a first-name basis with all 100 billion or so of the neurons in your nervous system. If you tasked each neuron only with the job of being conscious of itself, you might just about be able to do it. Unfortunately, you probably couldn’t concentrate on much else.
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