Cells in the visual cortex—the surf

Cells in the visual cortex—the surface layers at the back of the brain—have two important jobs to do. They have to analyze the depth of objects in the visual world, and they have to detect discontinuities between one object and another. The same cells are involved in both processes—but how are the two overlapping systems organized? Using a new technique, Gary Blasdel and Guy Salama of the University of Pittsburgh in the US have produced pictures of the visual cortex of macaque monkeys that demonstrate the two systems in action.