React

An introduction to the amazing functions of the human body's nervous system. This extremely advanced part of our biology is always at work interpreting the world we encounter and helping us decide what to do, and how to react. The secrets of our thoughts and decisions are locked into this astonishing network of cells, nerves, and fibers.

The brain is mission control of the human body and the nervous system. Its 100 billion cells are processing data an incredible speeds. The brain coordinates not only the major functions of the body, but it also is the hub where information is interpreted and stored, and then turned into action. We have the brain to thank for the unique abilities of our species.

All sight is translated into electrical impulses via the retina to the brain. The eye picks up information in the form of light. This light is instantaneously transformed into electricity, which shoots up to the brain. Once there, the electricity is decoded and formed into a picture. The information is traveling at speeds nearing 300mph, and the stream of data never stops.

Pain is a phenomenon that is deeply intertwined with the brain and nervous system. When something is wrong with the body, signals travel to our brain as neural impulses. These impulses are then interpreted by the brain as pain, which is basically the body's signal to us that we need to fix something.

Jason Little lost his hand in a car accident, which he thought meant the end of being able to sense touch in that part of his body forever. Years later, he's now the first user of a new wireless interface that connects to his prosthetic arm and allows him to actually feel things in his phantom limb. His brain is able to interpret new signals in a way they once did.

Through the lens of a boxer, a first responder, a cell tower climber and a man with a bionic limb, go deep into the universe of the most powerful machine on earth: the human brain and the vast nervous system it controls.