The function of dendritic spines: devices subserving biochemical rather than electrical compartmentalization

Dendritic spines are tiny, specialized protoplasmic protuberances that cover the surface of many neurons. First described by Ramon y Cajal(199 1) in light microscopic studies of Golgistained tissue, they are among the most striking subcellular features of many neurons. Spines serve as the major target for excitatory synaptic input onto principal neurons in the hippocampus, the neocortex, and other brain regions. Their intimate association with synaptic traffic suggests some critical role in synaptic transmission and plasticity. We here review experimental data and theoretical models with respect to the putative role of dendritic spines in the induction and retention of synaptic plasticity.