The viruses used to deliver the light-sensitive proteins can be engineered to target very specific clusters of brain cells.

FORBES: Magazine Article

Threaded on a wire one-fifth the thickness of a human hair, these tiny seeds of light can be injected to activate special networks of light-sensitive neurons.

WSJ: Brain Science: Mysterious Neural Circuitry Becomes Viewable

It is an interesting triple "coincidence, " which probably evolved over time, that our eyes are most sensitive to yellow-green light, which happens to be the characteristic color of sunlight as well as the color that can most easily be transmitted through the Earth's atmosphere.

CNN: Why gamma-ray burst shocked scientists

Problems included a penchant for picking up dirt and fingerprints (the price you pay for a beautiful glossy face, we suppose), a cramped nav key layout with the tricky touch-sensitive Navi Wheel front and center, audio performance that wasn't bad but was expected to be far better in light of the dedicated DSP, and a "shovel"-like feel in the hand, a symptom of the phone's generous dimensions.

ENGADGET: Nokia N96 gets in-depth review months ahead of release