 Look at even a simple black-and-white sign and your brain is doing a lot of work to make sure you see it properly and are ready to respond. Scientists know a lot about how the retina first picks up visual information and how that information is carried to other parts of the brain, namely to the visual cortex. It's there that thin layers of neurons create two equally important maps, spatial location and orientation. But exactly how those maps are made and co-exist has been a huge mystery. Now, researchers at the Moxplonk Institute for Neuroscience in Florida have uncovered a simple system that allows the cortex to divvy up the job and present faithful renderings of the outside world. Vision begins in the retina with special cells that respond either to increases in light or to increases in dark. These on-and-off pathways eventually converge onto single cells in the cortex. To create a neural representation of location, neighboring columns of these neurons handle little bits of adjacent visual space in a one-to-one mapping. Individual neurons respond selectively to particular orientations and are also organized in columns, with each stack responsible for a single angle and bordering columns covering other angles. To find out how these different mapping systems come about at the same time in the same cells, researchers used an advanced imaging technique to view the on-and-off response regions in hundreds of individual cortical neurons in the tree shrew brain. They found the off responses were extremely precise, restricted to small regions of visual space and reflecting the known map of location. The on responses, however, appeared jumbled, spread out over a larger region of visual space. But that didn't mean there wasn't an underlying organization. The researchers found that these seemingly disordered on responses were actually highly structured, not for location, but for orientation. The results suggest a visual system that uses off responses to convey information about location and on responses to detect the orientation of borders. It makes sense that the off responses would be used to map location because off-retinal cells have properties that allow them to carry more fine-scale spatial information than on cells. The fact that the on responses surround the off responses is also key. Every column of cells has this same organization. As a result, if you sample columns of neurons in a straight line along the cortical surface, the region of visual space captured by the off responses also moves in a line. At the same time, the region of visual space captured by the on responses rotates around, creating the map of orientation preference. Together, the resulting uninterrupted coverage is especially handy for detecting depth and motion. In addition to the tree shrew, other researchers have found a similar type of organization in CATS, suggesting it might be a common organizational principle in mammals.