5) To what extent do events occurring during regeneration re­ semble those seen in development? Questions like these remain open, particularly in relation to the mammalian central nervous system and to the effects of lesions or disease. The first chapters of this volume are concerned primarily with normal and abnormal development of the nervous system. New concepts have emerged over the past few years as a result of experiments made on the development of the higher nervous system in mammals. Thus, the principles of cell death, competition, selective retraction of specific processes, and the effects of abnormalities on the development of the rest of the system have now been extensively investigated. In addition, considerable information is available about biochemical changes during normal and abnormal development in the human. At the other end of the scale, in invertebrates it is now possible to follow cell lineage and to define the origin and fate of a sin­ gle neuron of known function together with its processes. While an understanding of development is clearly important for studying basic mechanisms of repair and regeneration, one cannot expect the processes to be identical or even comparable in the two situations. For example, cell migration, guidance by radial glial fibers, selective cell death, and the critical periods for competition, sprouting, and retraction observed in the visual system can hardly playa part in repair.

A Synoptic View of the Development of the Vertebrate Central Nervous System.- Normal and Abnormal Development of the Human Nervous System.- Factors That Influence Neural Development in Nematodes.- Acute Neural Reaction to Injury.- Molecular Events in Axonal Regeneration.- Transplantation of Neurons and Sheath Cells - A Tool for the Study of Regeneration.- Guidance of Axons During Development and After Nerve Injury.- Regeneration of Synapses.- Cell Recognition and Specific Synapse Formation.- Factors Involved in the Regulation of the Survival and Differentiation of Neurons.- Regeneration and Repair of the Nervous System: Clinical Aspects.- Recovery Mechanisms in the Mammalian Brain.- Clinical Evaluation of Injury and Recovery.- Adaptive and Maladaptive Regeneration in the Spinal Cord.- Temporal Changes After Spinal Cord Injury.- Electroneuroprostheses: Usefulness in Rehabilitation.- Neural Development: Implications for Recovery from Injury Group Report.- Early Responses to Neural Injury.- Factors Involved in the Restoration of Specific Neural Connections.- Restoration of Function.- List of Participants.- Author Index.