New approaches to neural circuits in behavior.

A fundamental goal of neuroscience is to understand how the brain represents the world. If we consider the neurons of the brain to be one system and the external world to be another system, how do the two systems interact, and by what translational code does the former represent the latter? Recent advances in imaging neural activity, genetically altering specific neural circuits, and genetic tools for the direct manipulation of neural activity are beginning to shed light on this critical question. We review recent advances in these areas that illustrate a path to addressing this fundamental question.