CLOSING THE LOOP: A fiber-optic thread delivers light to the brain to stimulate neurons. Microelectrodes measure changes in local voltage, and computer software uses the data to generate an average firing rate for hundreds of neurons. Researchers designed the program to instantaneously adjust the brightness of the LED light to keep the firing rate within a desired range.© GEORGE RETSECK
Optogenetics, a technique that transfects genes for light-activated ion channels into neurons to excite or inhibit the cells, has given scientists incredible control over neuronal behavior. Until now, micromanaging cells’ activity has not been so easy, as such precise control requires real-time feedback from the neurons themselves. Neuroscientists Steve Potter and Jonathan Newman of Georgia Tech and Emory University’s Laboratory for NeuroEngineering and their colleagues designed a system called an optoclamp that measures that feedback and instantaneously processes it into a command to increase or decrease the intensity of light being used to stimulate neurons.
FIRE AWAY: Channelrhodopsins—introduced via transgenes— in neuronal membranes are light sensitive. When activated, the channels transport positive ions (cations) into the neurons, causing them to fire.
See full infographic: WEB | PDF© GEORGE RETSECK
“It’s essentially a neuro thermostat,” ...
