Development of the Nervous System of Invertebrates

The complex architecture of the nervous system is the result of a stereotyped pattern of proliferation and migration of neural progenitors in the early embryo, followed by the outgrowth of nerve fibers along rigidly controlled pathways, and the formation of synaptic connections between specific neurons during later stages. Detailed studies of these events in several experimentally amenable model systems indicated that many of the genetic mechanisms involved are highly conserved. This realization, in conjunction with new molecular-genetic techniques, has led to a surge in comparative...

The complex architecture of the nervous system is the result of a stereotyped pattern of proliferation and migration of neural progenitors in the early embryo, followed by the outgrowth of nerve fibers along rigidly controlled pathways, and the formation of synaptic connections between specific neurons during later stages. Detailed studies of these events in several experimentally amenable model systems indicated that many of the genetic mechanisms involved are highly conserved. This realization, in conjunction with new molecular-genetic techniques, has led to a surge in comparative neurodevelopmental research covering a wide variety of animal phyla over the past two decades. This chapter attempts to provide an overview of the diverse neural architectures that one encounters among invertebrate animals, and the developmental steps shaping these architectures.