Introduction

The field of spinal motor neurobiology has grown dramatically over the last decade. One can argue that our understanding of spinal motoneurons and functionally related interneurons at both the cellular and systems levels advanced during the past 10 years as much as at any time since neurobiologists, including Sir Charles Sherrington, David Lloyd, and John Eccles established the foundations of the field. It was a relatively simple task, therefore, to identify topics to fill this book. By contrast, it was not easy to restrict the number of topics and contributors. The chief guiding principle used to select contributions to the book was one of providing a broad description of recent conceptual and technical advances in the field. This principle is met by chapters which collectively cover topics ranging from genetics to kinematics, examining cells, tissues, or whole animals, in species ranging from fish to humans that are normal, injured, or diseased, using techniques including immunocytochemisty, optical imaging, and electrical and mechanical analyses. Despite the breadth of coverage, our book is not comprehensive. Fortunately, the reader can compensate for some of our omissions by looking at recent books, including,

Neuronal Mechanisms for Generating Locomotor Activity,

O. Kiehn, R.M. Harris-Warrick, L.M. Jordan, H. Hultborn, and N. Kudo, Eds., 1998, and

Presynaptic Inhibition and Neural Control,

P. Rudomin, R. Romo, and L. Mendell, Eds., 1998. The reader will find that each chapter is a rich source of information relevant

to a variety of issues. Indeed, these features made it difficult to sequence the chapters, which might have been arranged in several ways other than the one chosen. The versatility expressed by each chapter also defies adequate description. Nonetheless, the following few comments describing each chapter are offered to give the reader a rough notion of content.