The scope of neuroscience is virtually limitless—it is nothing less than the seeking by the human brain to understand itself. Small wonder that the field draws on other scientific disciplines, some closely related and others that might at first appear more distant: cellular and molecular biology, behavioral sciences, and computational science, but also quantum mechanics and the new field of chaos theory. (This last may soon offer models for some of the processes that take place in integrating information—a task at which the human brain excels.) In addition, neuroscience research in the future will depend more on sophisticated technologies for observing the brain at work and for recording and sorting the flood of information that can be obtained. Computerized databases of neural circuitry—an open archive of the pathways and connections of any of the brain's 100 billion nerve cells—could provide answers and save time for countless research projects. The development of such tools has been proposed by a committee of the Institute of Medicine.
Within neuroscience itself, research progresses by means of loops, or back-and-forth exchanges between areas of inquiry that are mutually informative. One of the essential loops occurs between macrobiology and molecular biology; it goes from sophisticated measures of behavior to the precise identification of the nerve cells that underlie a particular movement or perception or memory, and then back again to the animal's behavior. In this connection, it is clear that curtailing the macrobiological studies, under pressure from nonscientists to abandon animal testing, works to the detriment of the whole enterprise; for without behavioral studies as a way of checking theories in the “real world,” cellular or molecular explanations of how the brain works can advance only a short way before sinking into conjecture. Likewise, in the examination of the human brain, the loop between research and clinical practice means that each side provides the other with the tools to proceed further. The study of schizophrenia is a notable example. Clinicians—psychiatrists and psychologists—have assembled the many forms and clinical signs of this disorder under a single heading; molecular biologists and geneticists are tracing patterns of in-