Description
The assembly of neural circuits involves multiple sequential steps such as the specification of cell types, their migration to proper brain locations, morphological and physiological differentiation, and the formation and maturation of synaptic connections. This intricate and often prolonged process is guided by elaborate genetic mechanisms that regulate each developmental event. Evidence from numerous systems suggests that each cell type, once specified, is endowed with a genetic program that directs its subsequent development. This cell intrinsic program unfolds in respond to, and is regulated by, extrinsic signals, including cell-cell and synaptic interactions. To a large extent, the execution of this genetic program is achieved by the expression of specific sets of genes that support distinct developmental processes. Therefore, a comprehensive analysis of the developmental progression of gene expression in synaptic partners of neurons may provide a basis for exploring the genetic mechanisms regulating circuit assembly.