You Can Now Wirelessly Control a Mouse Using Optogenetics

Scientists at Stanford University have changed the game of optogenetics by making it wireless. You can now manipulate brain activity in mice without using a bunch of wires attached to their head.

What is optogenetics?

Optogenetics is a technique invented to manipulate brain activity using light. Developed in 2010, this method is used to study the activities of brain and spinal cord by mapping how they respond to light. As the name suggests, this uses a combination of ‘optics’ (light) and ‘genetics’ (genes). In order to make them sensitive to light, neurons are genetically modified to express light-sensitive proteins called opsins. Since its inception, optogenetics has revolutionized the field of (neuroscience); it has provided answers to pressing questions in the field of Parkinson’s, pain management, and stroke.

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The latest in optogenetics: wireless implantable devices

Traditionally, optogenetics uses fiber optic wires attached to the mouse’s head to deliver the light for stimulation. While this setup might work for a mouse in an enclosed cage, it is quite restrictive when studying mice behaviors like burrowing and interactions with other mice. Also, attaching the wires before every experiment disrupts their natural rhythm, possibly stressing them out. These factors could confound the results obtained for studies on mood disorders like depression or schizophrenia, which heavily rely on social interactions. The Bio-X team at Stanford University has found the perfect solution to unfettering the mice.

How does this device work?

Building the implantable light-emitting device wasn’t difficult for the scientists. Powering the device was. A localized power source that would track the mouse’s movements throughout the experiment was too bulky and would defeat the purpose. So, Dr. Ada Poon, one of the researchers on this team had the idea of using the mouse’s own body to power the device. Here’s how they made it work: they first built a cavity that could amplify and store radio-frequency energy.

In order to prevent it from getting out, they enclosed the cavity using a grid that had holes smaller than the wavelength of radio waves. This way, the energy stays trapped inside, except when something comes in contact with the grid⎯say a mouse. Since the wavelength of this light is the same as that would resonate in a mouse. Therefore, when in contact with the grid the mouse essentially acts as conduit channeling the radio frequency energy to power the light-emitting device. We now have a mouse powering a tiny device that can be implanted under the skin, and light up wherever the mouse chooses to go.

This wireless innovation will definitely make behavioral studies in mice easier and free from any confounding factors. Also, since we do not have genetically engineered neurons in our bodies, we don’t have to worry about these devices controlling our brains anytime soon.

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On that light tech grind…