The present volume has been written primarily for the advanced student and the mature investigator. The book will be of value to the student because it includes representative research problems on a variety of topics, and significant for the mature investigator, because it can help bring him up to date on specific topics in limbic and autonomic nervous system research, an area which has undergone spectacular growth, particularly during the last ten years. The twelve chapters deal with subject matter that falls loosely into four major subtopics-basic sensory and regulatory mechanisms, emotional processes, cardiovascular processes and learning, and low arousal states-but each chapter represents recent research in one particular area, and stands as a self-contained unit. I am indebted to the many authors and publishers for their aid in granting permission to reproduce quotations, tables, and figures from their works. Specific acknowledgments are made in the text. Leo V. DiCara Ann Arbor Contents Basic Sensory and Regulatory Mechanisms Chapter 1 The Olfactory System and Behavior Bernice M. Wenzel I. Introduction ........................................ 1 2. Background ........................................ 2 2.1. Rhinencephalon ................................ 2 2.2. The Direct Olfactory System and Its Connections .... 3 2.3. Olfactory Lesions and Nonolfactory Behavior ....... 7 3. Effects of Lesions in the Direct Olfactory System ......... 8 3.1. Orienting and Habituation ....................... 9 3.2. Activity ....................................... 12 3.3. Avoidance Learning. . . .. . . . . . . . . . . . . . . . . . . 13 . . . . . . 3.4. Appetitive Learning. . . . . . . . . . . . . . . . . . . . . . 16 . . . . . . .