The technological seeds of a Manhattan project-style scientific enterprise, the optical reverse-engineering of brain circuits to crack the neural code, have recently been planted at Stanford.
The brain is a high-speed dynamical system consisting of different players that are intertwined and that cannot be separately controlled using conventional methods. For this reason, until recently we have not been able to speak the language of the brain (with millisecond timescale and cell-specific resolution), and in 1979 Francis Crick called for a technology by which all neurons of just one type could be controlled, "leaving the others more or less unaltered".
Tools from the Deisseroth laboratory at Stanford over the past four years have responded to this challenge. These include optical technologies for controlling neural circuits, using precisely-targeted delivery of light energy of different colors that is captured by neurons using nanoscale protein-based antennae, resulting in controlled activity of just the targeted cell types with millisecond precision. Light is delivered by fiberoptics; while light encounters all cell types, only the desired cell type is light-sensitive and responds. Using different optogenetic probes, cells can be turned on or off with millisecond precision and in different combinations.
These tools have now been used to optically deconstruct Parkinsonian neural circuitry, setting the stage both for cracking the neural codes of normal brain function, and for re-engineering neural circuits in disease.