In his kickoff lecture for this series on neuroscience, Mriganka Sur provides both a current overview of brain models and function, and a peek at his own research. From the moment of conception, a developing animal begins to grow cortical pathways and networks that will eventually allow it to respond to the world outside. These increasingly sophisticated networks—for hearing, vision, touch—provide feedback to the evolving brain. For humans, at least half the brain is devoted directly or indirectly to processing vision, says Sur. Yet there is a single model for understanding how vision works: orientation selectivity. Regions of neural cells react only to specific stimuli, such as vertical or horizontal stripes, obliques or diagonals. Images of these activated cell networks from Sur’s lab resemble pinwheels. In Sur’s research on newborn ferrets, he rewired visual inputs to the animals’ hearing center, and found the same patterned responses to specific shapes among cells—more pinwheels. In essence, Sur enabled ferrets to “see” through their hearing cortex. This dramatic experiment demonstrates the plasticity of brain networks, and suggests there might be ways to repair human brains after stroke or other traumas.