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.

Throughout his remarkable career, Donald Pfaff has demonstrated that by choosing problems and methods with care, biologists can study the molecular mechanisms of brains more complex than those of fruit flies, snails, roundworms, and other invertebrates. His half century in the lab, starting with his discovery of hormone receptors in the brains of mammals and leading to the first detailed account of a neural circuit for mammalian behavior, puts him in a unique position to survey the origins and development of behavioral neurobiology and the current state of research. How the Vertebrate Brain Regulates Behavior offers a close-up, conversational perspective on scientific struggles and successes throughout a fifty-year quest to understand how behavior is regulated in a complex organism.

In graduate school, when Pfaff expressed a desire to study behavioral regulation, his advisor suggested focusing on hormones. Pfaff’s investigation into the hormonal basis of female sexual behavior in laboratory rats led him to a comprehensive appreciation of how hormone-dependent neurons work through neural circuits to produce discrete behaviors among all vertebrates. This breakthrough, along with other researchers’ findings, established a link between molecular biology and neuroscience that opened up a fruitful new field of inquiry.

Pfaff’s approach is to focus on one solvable problem and explore it from many angles. He begins with a single observed behavior and traces its regulation through a series of biological mechanisms—from hormones to genes to neural circuits. Pfaff’s relentless pursuit of his goals continues to inspire neuroscientists today.