Casting light on diseased circuitry: optogenetics helps identify cellular targets of deep brain stimulation. First, specific cells are treated in a way that makes them sensitive to stimulation by blue light. Then an optical fiber is implanted in the subthalamic nucleus (STN) region of the brain. Treating the brain with rapid flashes of blue light activates neurons (green and purple structures) in the STN and cortex, which improves disease symptoms. This optogenetic result provides important scientific insight into the affected brain circuits.

Credit: Zina Deretsky, National Science Foundation

Casting light on diseased circuitry: In the first application of optogenetics to brain disease, the combined use of light-activated proteins and fiberoptics helps Parkinsonian animals move more easily and quickly. When flashes of blue light are delivered to the ends of neurons at the surface of the brain (blue fiber), researchers detect activation of cells deep within the brain (yellow electrode). The red line (within the circle) shows an untreated animal's path, and the blue line shows the animal's path, over the same amount of time, when treated with light delivered through the fiberoptic. The animals' ability to move more quickly and easily, a result of optogenetic treatment, provides important scientific insight into the affected brain circuits.

Credit: Viviana Gradinaru, Murtaza Mogri, and Karl Deisseroth, Stanford University

The researchers' findings are published in the April 17, 2009, issue of Science magazine.

Credit: Copyright 2009 AAAS