This series of books, "Readings from the Encyclopedia of Neuroscience." consists of collections of subject-clustered articles taken from the Encyclopedia of Neuroscience. The Encyclopedia of Neuroscience is a reference source and compendium of more than 700 articles written by world authorities and covering all of neuroscience. We define neuroscience broadly as including all those fields that have as a primary goal the under­ standing of how the brain and nervous system work to mediate/control behavior, including the mental behavior of humans. Those interested in specific aspects of the neurosciences, particular subject areas or specialties, can of course browse through the alphabetically arranged articles of the En­ cyclopedia or use its index to find the topics they wish to read. However. for those readers-students, specialists, or others-who will find it useful to have collections of subject-clustered articles from the Encyclopedia, we issue this series of "Readings" in paperback. Students in neuroscience, psychology, medicine, biology, the mental health professions, and other disciplines will find that these collections provide concise summaries of cutting­ edge research in rapidly advancing fields. The nonspecialist reader will find them useful summary statements of important neuroscience areas. Each collection was compiled, and includes an introductory essay, by an authority in that field.