New tricks and old spines

摘要

Imaging of brain structures in living mice reveals that learning new tasks leads to persistent remodelling of synaptic structures, with each new skill associated with a small and unique assembly of new synapses.rnThe notion that structural changes in brain circuitry underlie certain forms of learning is widely accepted, yet this belief has been frus-tratingly difficult to establish experimentally. Two studies, one by Xu et al. (page 915) and one by Yang et al. (page 920) published in this issue, provide compelling evidence that learning new motor tasks (and acquiring new sensory experiences) is associated with the formation of new sets of persistent synaptic connections in motor (and sensory) regions of the mouse brain. These findings suggest that synapse assemblies, rather than cell assemblies, might be viewed as the elementary entities (engrams) of stored memories.