Throughout the life of the vertebrates, the core of the central nervous system, sometimes called the reticular formation, has retained the power to commit the whole animal to one mode of behavior rather than another. Its anatomy, or wiring diagram, is fairly well known, but to date no theory of its circuit action has been proposed that could possibly account for its known performance. Its basic structure is that of a string of similar modules, wide but shallow in computation everywhere, and connected not merely from module to adjacent module, but by long jumpers between distant modules. Analysis of its circuit actions heretofore proposed in terms of finite automata or coupled nonlinear oscillators has failed. A radical set of nonlinear, probabilistic hybrid computer concepts is proposed as a guideline for specifying the operational schemata of the above modules. Using the smallest numbers and greatest simplifications possible, a reticular formation concept consisting of 12 anastomatically-coupled modules stacked in columnar array was arrived at. A simulation test of its behavior shows that despite its 800-line complexity, it still behaves as an integral unit, rolling over from stable mode to stable mode according to abductive logical principles, and as directed by its succession of input 60-tuples. The concept employs the following design strategies: modular focusing of input information; modular decoupling under input changes; modular redundancy of potential command (modules having the most information have the most authority); and recruitment and inhibition around reverberatory loops. (Author).

A succinct, neurobiological explanation of the pathways that 'wake up the brain' from deep anesthesia, sleep and brain injury.

By J OHN A. HRONES Provost, Case Institute 0/ Technology SYSTEMS have been the subject of man's study for many hundreds of years. Thus, the solar system has been the concern of the astronomer. The study of the allocation of material and human resources within the boundaries of an industrial firm or a government has been the concern of the economist. The subject of such studies have been widely known as economic systems. Medieal men have worked with the human body. Thus, man has attempted to deal with a complicated array of interconnected elements since the very earliest of recorded time. In his attcmpt to improve his understanding of physieal systems the need to concentrate on a specific kind of system, e.g., the solar system. the human body, became more imperative. However in recent years there has begun to grow and develop an increasing number of people who are working on thc development of general systems theory and analysis. Such a development is based upon the belief that certain view points, certain kinds of mathematics and technologieal procedures can be applied to a wide variety of important systems with considerable profit. The pres sures for the development of such a body of knowledge grew with the de velopment of a technologieal socicty.

The brain ... There is no other part of the human anatomy that is so intriguing. How does it develop and function and why does it sometimes, tragically, degenerate? The answers are complex. In Discovering the Brain, science writer Sandra Ackerman cuts through the complexity to bring this vital topic to the public. The 1990s were declared the "Decade of the Brain" by former President Bush, and the neuroscience community responded with a host of new investigations and conferences. Discovering the Brain is based on the Institute of Medicine conference, Decade of the Brain: Frontiers in Neuroscience and Brain Research. Discovering the Brain is a "field guide" to the brainâ€"an easy-to-read discussion of the brain's physical structure and where functions such as language and music appreciation lie. Ackerman examines: How electrical and chemical signals are conveyed in the brain. The mechanisms by which we see, hear, think, and pay attentionâ€"and how a "gut feeling" actually originates in the brain. Learning and memory retention, including parallels to computer memory and what they might tell us about our own mental capacity. Development of the brain throughout the life span, with a look at the aging brain. Ackerman provides an enlightening chapter on the connection between the brain's physical condition and various mental disorders and notes what progress can realistically be made toward the prevention and treatment of stroke and other ailments. Finally, she explores the potential for major advances during the "Decade of the Brain," with a look at medical imaging techniquesâ€"what various technologies can and cannot tell usâ€"and how the public and private sectors can contribute to continued advances in neuroscience. This highly readable volume will provide the public and policymakersâ€"and many scientists as wellâ€"with a helpful guide to understanding the many discoveries that are sure to be announced throughout the "Decade of the Brain."