学习和记忆形成被认为与脑回路的结构变化相关。这种关联的实验证明一直难以找到，但现在两个小组利用双光子成像发现，突触网络重塑与稳定的记忆存储密切相关。在训练小鼠努力接触某一目标（即所谓的“reaching task”）的实验中，Xu等人发现皮层神经元几小时内有一个结构反应——新树状突脊的产生。不同突脊以及由此产生的假定突触集编码截然不同的、通过学习获得的运动技能。（生物谷Bioon.com）
生物谷推荐原始出处：
Nature 462, 915-919 (17 December 2009) | doi:10.1038/nature08389
Rapid formation and selective stabilization of synapses for enduring motor memories
Tonghui Xu1,3, Xinzhu Yu1,3, Andrew J. Perlik1, Willie F. Tobin1, Jonathan A. Zweig1, Kelly Tennant2, Theresa Jones2 & Yi Zuo1
1 Department of Molecular, Cell and Developmental Biology, University of California Santa Cruz, Santa Cruz, California 95064, USA
2 Institute for Neuroscience, Department of Psychology, University of Texas at Austin, Austin, Texas 78712, USA
3 These authors contributed equally to this work.
Correspondence to: Yi Zuo1 Correspondence and requests for materials should be addressed to Y.Z.
Novel motor skills are learned through repetitive practice and, once acquired, persist long after training stops1, 2. Earlier studies have shown that such learning induces an increase in the efficacy of synapses in the primary motor cortex, the persistence of which is associated with retention of the task3, 4, 5. However, how motor learning affects neuronal circuitry at the level of individual synapses and how long-lasting memory is structurally encoded in the intact brain remain unknown. Here we show that synaptic connections in the living mouse brain rapidly respond to motor-skill learning and permanently rewire. Training in a forelimb reaching task leads to rapid (within an hour) formation of postsynaptic dendritic spines on the output pyramidal neurons in the contralateral motor cortex. Although selective elimination of spines that existed before training gradually returns the overall spine density back to the original level, the new spines induced during learning are preferentially stabilized during subsequent training and endure long after training stops. Furthermore, we show that different motor skills are encoded by different sets of synapses. Practice of novel, but not previously learned, tasks further promotes dendritic spine formation in adulthood. Our findings reveal that rapid, but long-lasting, synaptic reorganization is closely associated with motor learning. The data also suggest that stabilized neuronal connections are the foundation of durable motor memory.
