The major goal of developmental neurobiology is to understand how the nervous system is put together. A central theme that has emerged from research in this field over the last several decades is the crucial role of trophic interactions in neural assembly, and indeed throughout an animal's life. Trophic—which means nutritive—refers to long-term interdependencies between nerve cells and the cells they innervate.

The theory of trophic effects presented in this book offers an explanation of how the vertebrate nervous system is related to—and regulated by—the body it serves. The theory rationalizes the nervous system's accommodation, throughout life, to the changing size and form of the body it tenants, indicating the way connections between nerve cells change in response to stimuli as diverse as growth, injury, experience, and natural selection.

Dale Purves, a leading neurobiologist best known for his work on the formation and maintenance of synaptic connections, presents this theory within the historical setting of earlier ideas about neural organization—from Weiss's theory of functional reorganization to the chemoaffinity theory championed by Sperry. In addition to illuminating eighty years of work on trophic interactions, this book asks its own compelling questions: Are trophic interactions characteristic of all animals or only of those with complex nervous systems? Are trophic interactions related to learning? What does the trophic theory of neural connections imply about the currently fashionable view that the nervous system operates according to Darwinian principles?

Purves lays the theoretical foundation for practical exploration of trophic interactions as they apply to neural connections, a pursuit that will help us understand how our own nervous systems generate change. The ideas in this book not only enrich neurobiology but also convey the profound relevance of neuroscience to other fields of life science.

Arousal is fundamental to all cognition. It is intuitively obvious, absolutely necessary, but what exactly is it? In Brain Arousal and Information Theory, Donald Pfaff presents a daring perspective on this long-standing puzzle. Pfaff argues that, beneath our mental functions and emotional dispositions, a primitive neuronal system governs arousal. Employing the simple but powerful framework of information theory, Pfaff revolutionizes our understanding of arousal systems in the brain.

Starting with a review of the neuroanatomical, neurophysiological, and neurochemical components of arousal, Pfaff asks us to look at the gene networks and neural pathways underlying the brain’s arousal systems much as a design engineer would contemplate information systems. This allows Pfaff to postulate that there is a bilaterally symmetric, bipolar system universal among mammals that readies the animal or the human being to respond to stimuli, initiate voluntary locomotion, and react to emotional challenges. Applying his hypothesis to heightened states of arousal—sex and fear—Pfaff shows us how his theory opens new scientific approaches to understanding the structure of brain arousal.

A major synthesis of disparate data by a preeminent neuroscientist, Brain Arousal and Information Theory challenges current thinking about cognition and behavior. Whether you subscribe to Pfaff’s theory or not, this book will stimulate debate about the nature of arousal itself.