Neuroscience examines the structure and function of the human brain and nervous system. Neuroscientists use cellular and molecular biology, anatomy and physiology, human behavior and cognition, and other disciplines, to map the brain at a mechanistic level.
Humans have an estimated hundred billion neurons, or brain cells, each with about a thousand connections to other cells. One of the great challenges of modern neuroscience is to map out all the networks of cell-to-cell communication—the brain circuits that process all thoughts, feelings, and behaviors. The resulting picture, emerging bit by bit, is known as "the connectome." The ability of the brain to elaborate new connections and neuronal circuits—neuroplasticity—underlies all learning.
Biology and psychology unite in the field of neuroscience, to tackle questions such as the brain’s role in pain perception or the underlying cause of Parkinson’s disease. Computer simulations, imaging, and other tools give researchers and medical experts new insight into the physical anatomy of the brain, its five million kilometers of wiring, and its relationship to the rest of the mind and body.