This state-of-the-art review links the experimental data into a cohesive and critical account of CNS regeneration. Research findings are discussed in terms of their relevance to one (or more) of thirteen hypotheses concerned with regeneration in the mammalian CNS. Research findings reviewed include: regeneration in developing mammals and in submammalian vertebrates, the use of transplants and/or pharmacological treatments, in vitro studies on neurotrophic and neurite promoting factors and their potential relevance to CNS regeneration in vivo, and in vitro studies on the types of glial cells that may be responsible for enhancing or suppressing axonal re-growth.

1 Hypotheses Concerned with Regeneration in the Mammalian Central Nervous System

1.1 Introduction
1.2 Histopathological Response to Trauma
1.3 Successful Regeneration of Some Neurons in the Mammalian CNS
1.4 Hypotheses to Explain the Limited Regenerative Capacity of CNS Neurons
2 In Vivo Experimental Approaches to Hypotheses Concerned with Regeneration in the Mammalian CNS
2.1 Introduction
2.2 Submammalian Vertebrates
2.3 Developmental Events in Mammals
2.4 Morphological and Biochemical Assessment of Regeneration in Mammals
2.5 The Use of Transplants
2.6 Pharmacological Approaches
2.7 Conclusions
3 In Vitro Experimental Approaches to Hypotheses Concerned with Regeneration in the Mammalian CNS
3.1 Introduction
3.2 The Role of the Microenvironment - Neuronotrophic Factors
3.3 The Role of the Microenvironment - The Substrate and Substrate-Bound Neurite Promoting Factors
3.4 The Role of the Microenvironment - Humoral Neurite-Promoting Factors
3.5 The Role of the Microenvironment - The Non-neuronal Cells
4 Conclusions
References.