After suffering damage to the right side of his brain, a Swiss stroke patient developed a puzzling symptom. Although the left side of his body was weak and he had trouble seeing objects in his left field of vision, what concerned him most was the blandness of the hospital food. The stroke had left the man obsessed with fine dining, a phenomenon later dubbed “gourmand syndrome.” In his diary, the patient wrote, “It is time for . . . a good sausage with hash browns or some spaghetti Bolognese, or risotto and a breaded cutlet, nicely decorated, or a scallop of game in cream sauce with spaetzle.” After recovering, he quit his job as a political journalist and became a food columnist (Regard & Landis, 1997).

Julie appears perfectly normal when you first meet her, but it soon becomes apparent that she lives in a bewildering place: the eternal present. Since suffering brain damage when a freight train hit her car, Julie has been unable to recall people and events from either the distant past or a few minutes ago. She cannot remember her daughter, who died in the accident. She knows she has a husband, but he must be reintroduced to her whenever she sees him. She can cook or make a phone call, but when she tries to read, the words from the start of the paragraph vanish by the time she gets to the end. She keeps meticulous notes about her day, but she feels she is faking her way through life (Mason, 2008).

These cases, and thousands like them, teach us that the 3-pound organ inside our skulls provides the bedrock for everything we do and think. When injury or disease affects the brain's functioning, life is inevitably altered physically, emotionally, or mentally. Sometimes the changes are subtle and even benign, as in the case of “gourmand syndrome.” All too often, as in Julie's case, they are not.

Meanwhile, discoveries about the brain constantly make headlines, as new research is announced and old puzzles begin to be solved. Consider these examples:

• A sleeping pill has restored awareness in some patients who spent several years in a “minimally conscious state” (which leaves the brain more intact than does a “persistent vegetative state,” from which there is no recovery). In such patients, awareness often waxes and wanes. But with the drug zolpidem, some people recover much greater awareness over time. The pill would put a healthy person to sleep, but, surprisingly, it seems to arouse certain people with brain damage and help the brain to function more normally (Chatelle et al., 2014).

• A brain-monitoring technique has allowed researchers to recreate visual images based on brain-wave activity (Nishimoto et al., 2011). By measuring how the brain responds while watching hours and hours of YouTube videos, researchers were able to reverse the process, and use the pattern of brain activity to predict which new images a person was viewing—a sort of “mind reading” based on the electrochemical activity of the brain.

• Recently, scientists at the Johns Hopkins University Applied Physics Laboratory fitted a man who had both of his arms amputated at the shoulder with dual-arm robotic prosthetics. The man could move his robotic prosthetic shoulders, elbows, and wrists and grasp objects, all through the use of signals emanating from his brain. This and other research raise hope that ”neural prosthetics” will one day help paralyzed and incapacitated people.

Neuroscientists in psychology and other disciplines study the brain and the rest of the nervous system in hopes of gaining a better understanding of normal behavior and of the outer reaches of what is possible for this organ. Cognitive neuroscientists explore the biological foundations of consciousness, perception, memory, and language; social neuroscientists focus on processes such as attachment and attitudes; affective neuroscientists study the nervous system's involvement in emotion, motivation, and stress; and behavioral neuroscientists study the biology of such basic processes as learning, conditioning, eating, and sex. You can see that this list covers basically everything that human beings feel and do. In this chapter, we will examine the structure of the brain and the rest of the nervous system as background for our later discussions of these and other topics.

At this very moment, your own brain, assisted by other parts of your nervous system, is busily taking in these words. Whether you are excited, curious, or bored, your brain is registering some sort of emotional reaction. As you continue reading, your brain will (we hope) store away much of the information in this chapter. Later in the day, your brain may enable you to smell a flower, climb the stairs, greet a friend, solve a problem, or laugh at a joke. But the brain's most startling accomplishment is its knowledge that it is doing all these things. This self-awareness makes brain research different from the study of anything else in the universe. Scientists must use the cells, biochemistry, and circuitry of their own brains to understand the cells, biochemistry, and circuitry of brains in general.

William Shakespeare called the brain “the soul's frail dwelling house.” Actually, this miraculous organ is more like the main room in a house filled with many alcoves and passageways—the “house” being the nervous system as a whole. Before we can understand the windows, walls, and furniture of this house, we need to become acquainted with the overall floor plan.