Recent progress has greatly expanded our view of how signaling pathways regulate the actin cytoskeleton in
post-synaptic spines. These studies reveal a complex interplay between pathways that highlight the role of the actin cytoskeleton
during the development of spines as well as in response to stimuli that modify synaptic strength. This review
discusses the results from these studies that include biochemical, cellular, and genetic approaches to understanding excitatory
synapse formation and function.