The brain is an extremely complex organ, containing more neurons than stars in the galaxy and operating on molecular, cellular, synaptic, circuit, systems, computational and psychological levels. Over 1 million new neural connections are made every day, further adding to the complexity of the brain.
Scientists attempting to understand the brain have focused on the idea of mapping it, creating a diagram of the network and interactions of neural structure. Many scientists, instead of directly studying the human brain, focus on studying the simpler brains of smaller organisms, chiefly invertebrates. A modern advance has been termed the "Brainbow," which uses techniques of Golgi staining and genetically "tagging" neurons to produce colorful fluorescent diagrams of brain activity.
When the nervous system and the brain encounter a sensation, the sensory input results in a series of electrical spikes, many of which "light up" entire regions of the brain. These electrical spikes transform sensory input into a form understandable to the organism itself. While the end goal of fully mapping and understanding how the brain processes and stores information has not yet been accomplished, technological breakthroughs, particularly in the areas of imaging and computer science, have made the goal much more feasible than before.