Rewiring the memory circuits

Learning and memory are thought to involve physical and functional changes to neuronal connections, but relatively little is known about structural changes to behaviour-relevant circuits. Two new studies highlight some of the physical alterations and mechanisms that may underlie learning and neural plasticity. Lai et al. analysed neurons participating in fear circuits: they found that fear learning induced a loss of dendritic spines, and that extinction of the fear caused a regrowth of spines in the same areas. Fu et al. reveal that repetitive activation of specific circuitry during motor learning can induce formation of new clusters of dendritic spines, which remain throughout prolonged learning sessions.