The dynamic cytoskeleton: backbone of dendritic spine plasticity.

Dendritic spines are small actin-rich protrusions on the surface of dendrites whose morphological and molecular plasticity play key roles in learning and memory. Both the form and function of spines are critically dependent on the actin cytoskeleton. However, new research, using electron microscopy and live-cell super-resolution microscopy indicates that the actin cytoskeleton is more complex and dynamic than originally thought. Also, exciting recent studies from several labs indicate that microtubules, once thought to be restricted to the dendrite shaft, can make excursions into the most distal regions of dendritic spines. Moreover, microtubule invasions of spines appear to be associated with changes in synaptic activity. Thus, it is likely that dynamic interactions between microtubules and actin filaments within dendritic spines play important roles in dendritic spine plasticity.