Optogenetics is a revolutionary new field of neuroscience in which brain neurons are genetically engineered with a light-sensitive protein so they glow when illuminated with a specific type of light. The exciting new field is a serious game-changer in mapping the human brain and discovering what makes it tick. Now researchers have reversed the technique, this time genetically engineering the neurons with proteins that glow when fired. The new technique allows neuroscientists to watch neurons quite literally communicating with eachother. You can watch the video above, and learn more about this amazing new tool by visiting NewScientist.com. You can also watch two terrific videos below which explain more about optogenetics. For more amazing stories about the human brain be sure to visit The Human Brain on FEELguide.