Place-dependent Cell Adhesion, Process Retraction, and Spatial Signaling in Neural Morphogenesis

The establishment of a functioning neuroanatomy during development is obviously a multistage process. In its early stages, it calls upon cellular driving forces, neurite extension and retraction, and various interactions with cell adhesion molecules (CAMs) and substrate adhesion molecules (SAMs). These early events result in the formation of particular neuroanatomical structures (Edelman 1986, 1987a). Later, during synapse formation and the establishment of refined neural maps, activity-dependent effects of correlated signals drive the formation of specific synaptic contacts (Constantine-Paton et al. 1990). The combined results of early and late events is an intricate but specifically mapped neural structure able to respond appropriately to different inputs.