It has been established that neuroglia are involved in early neu- ronal growth, differentiation, and migration; these issues are well discussed in the companion volume entitled Neuron-Glia Interrela- tions During Phylogeny: I. Phylogeny and Ontogeny of Glial Cells. The present volume, Neuron-Glia Interrelations During Phylogeny: II. Plas- ticity and Regeneration, focuses on two aspects: (1) neuron-glia inter- relations as they relate to the physiological...