One critical way that the brain processes information is to create maps of the world around it. From the brain stem up to the cortex, the brain processes information like a very detailed mapmaker. The brain passes information upstream in steps, moving from the lower-level, more simply organized regions to the higher-level, more complex regions. At each step, the new region maps the neural firing patterns of the region below. It does this by recreating the spatial lay-out of the neurons of the other region. In this way, the brain builds a series of representations of both internal and external reality. These maps then serve as guides for action. They help the brain to regulate the internal states of the body, respond to objects in the environment, and respond to the neural patterns underlying our own thoughts and emotions. Another term for map is representation. This term is used frequently in discussing the brain.

When an arrangement in space in one system mimics that of another system, the first system is mapping the second. For example, when you draw two intersecting lines to show a visitor how to get to your house, you are mapping the streets where you live. The brain uses time in its maps as well as space, however. The sequence of firing patterns over time is also captured in the maps of the brain, similar to the way in which a musical theme repeats throughout a symphony.