Repetitive motor learning induces coordinated formation of clustered dendritic spines in vivo.
Repetitive motor learning induces coordinated formation of clustered dendritic spines in vivo.
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DOI：
10.1038/nature10844
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发表时间：
2012-02-19
期刊：
影响因子：
64.8
通讯作者：
Zuo, Yi
中科院分区：
文献类型：
--
作者：
Fu, Min;Yu, Xinzhu;Lu, Ju;Zuo, Yi
许多证据表明，哺乳动物大脑中的记忆是以不同的时空模式存储的。尽管最近在识别参与记忆编码的神经元群体方面取得了进展，但突触水平的机制仍然知之甚少。计算模型和电生理学数据已经表明，突触沿着树突分支的功能聚类导致突触输入的非线性求和，并且极大地扩展了神经网络的计算能力。然而，邻近的突触是否参与编码类似的记忆，以及任务特定的皮层网络如何在学习过程中发展仍然是难以捉摸的。使用经颅双光子显微镜，我们跟踪了运动皮层第5层（L5）锥体神经元的顶端树突，同时小鼠练习新的前肢技能。在这里，我们表明，三分之一的新的树突棘（突触后结构的大多数兴奋性突触）的学习过程中形成的收购阶段出现在集群中，大多数这样的集群是相邻的棘对。与非集群的对应物相比，这些集群的新棘更有可能在长时间的学习过程中持续存在，甚至在训练停止后很长时间。此外，新脊柱簇的形成需要重复相同的运动任务，并且后续新脊柱的出现伴随着簇中第一个新脊柱的加强。我们还表明，在控制条件下，新的脊柱出现，以避免现有的稳定的脊柱，而不是均匀添加沿着树突。然而，随后的新的刺簇克服了这样的空间约束，并形成在附近的相邻稳定的刺。我们的研究结果表明，集群的新突触沿着树突诱导的重复激活的皮层电路在学习过程中，提供了一个结构基础的空间编码的运动记忆在哺乳动物大脑。
Many lines of evidence suggest that memory in the mammalian brain is stored with distinct spatiotemporal patterns. Despite recent progresses in identifying neuronal populations involved in memory coding, the synapse-level mechanism is still poorly understood. Computational models and electrophysiological data have shown that functional clustering of synapses along dendritic branches leads to nonlinear summation of synaptic inputs and greatly expands the computing power of a neural network. However, whether neighboring synapses are involved in encoding similar memory and how task-specific cortical networks develop during learning remain elusive. Using transcranial two-photon microscopy, we followed apical dendrites of layer 5 (L5) pyramidal neurons in the motor cortex while mice practiced novel forelimb skills. Here we show that a third of new dendritic spines (postsynaptic structures of most excitatory synapses) formed during the acquisition phase of learning emerge in clusters, and the majority of such clusters are neighboring spine pairs. These clustered new spines are more likely to persist throughout prolonged learning sessions and even long after training stops, compared to non-clustered counterparts. Moreover, formation of new spine clusters requires repetition of the same motor task, and the emergence of succedent new spine(s) accompanies the strengthening of the first new spine in the cluster. We also show that under control conditions new spines appear to avoid existing stable spines, rather than being uniformly added along dendrites. However, succedent new spines in clusters overcome such a spatial constraint and form in close vicinity to neighboring stable spines. Our findings suggest that clustering of new synapses along dendrites is induced by repetitive activation of the cortical circuitry during learning, providing a structural basis for spatial coding of motor memory in the mammalian brain.
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影响因子：
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