Includes bibliographical references (p. 179-249) and index.

Machine generated contents note: Series Foreword -- Preface -- List of Abbreviations -- I Requirement for Motivational State Concepts -- A. Physics, Brain, and Behavior -- B. Motivation in Its Generalized and Specific Aspects -- C. Motivation for Females to Seek Males -- D. Hypothalamic and Preoptic Mechanisms Involved in Two Types of Motivational Change -- E. Summary -- II Ascending Arousal Systems Activated -- A. Ascending Reticular Activating Systems -- B. Structure of Arousal States -- C. Application to Sexual Behavior -- D. Clinical Observations on Human Awareness and Arousal -- E. Mood -- F. Summary -- III Descending Systems: The Importance of Opioid Peptides and Analgesia -- A. Opioid Peptides in Pain and Analgesia -- B. Analgesia Induced by Stress and Environmental Variables -- C. Hormonal Control of the Enkephalin Gene: One Paradox and Three Solutions -- D. Intimate Relations among Inhibitory Systems -- E. Hypothalamic Projections -- F. Gender Differences in Analgesia -- G. Pain and Sex: Similarity of Reproductive Behavior and Analgesia-Ascending and Descending Pathways -- H. Summary -- IV Inferences and Arguments -- A. Gene/Behavior Relationships: Application to Opioid Peptides -- B. Biological Importance of the Relations among Sex, Arousal, and Analgesia -- References -- Index.