Experience-dependent and cell-type-specific spine growth in the neocortex
Experience-dependent and cell-type-specific spine growth in the neocortex
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DOI：
10.1038/nature04783
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发表时间：
2006-06-22
期刊：
影响因子：
64.8
通讯作者：
Svoboda, Karel
中科院分区：
文献类型：
--
作者：
Holtmaat, Anthony;Wilbrecht, Linda;Svoboda, Karel
成年人新皮层的功能回路适应新的感觉体验，但潜在的突触机制仍然未知（1）。树突棘的生长和收缩以及突触的形成和消除可以改变大脑回路（2-7）。在小鼠桶状皮质中的第5 B层（L5 B）锥体神经元的顶端簇中，树突棘的子集在数天内出现和消失，而大多数棘持续数月（4- 6、8、9）。在基线条件下，新的脊椎大多是短暂的，很少存活超过一周。暂时性棘往往较小（4，5，9），而持久性棘通常较大（4- 6，8，9）。因为皮层中的大多数兴奋性突触发生在棘上，并且因为突触大小（10）和α-氨基-3-羟基-5-甲基-4-异恶唑丙酸（AMPA）受体的数量（11-13）与棘体积成比例，锥体神经元的兴奋可能是通过持久棘上的突触驱动的。在这里，我们测试是否产生和持久性棘的损失是由新的感官体验增强。我们在修剪交替胡须后重复成像树突棘一个月，这是一种诱导新皮层回路适应性功能变化的范例（14，15）。胡须修剪稳定新的刺和不稳定以前持久的刺。新的宿存刺总是形成突触。它们优先添加在L5 B神经元复杂的顶丛，而不是简单的簇。我们的数据表明，新的感觉经验驱动稳定的皮质神经元亚类的新刺。这些突触变化可能是特定新皮层回路的经验依赖性重塑的基础。
Functional circuits in the adult neocortex adjust to novel sensory experience, but the underlying synaptic mechanisms remain unknown(1). Growth and retraction of dendritic spines with synapse formation and elimination could change brain circuits(2-7). In the apical tufts of layer 5B (L5B) pyramidal neurons in the mouse barrel cortex, a subset of dendritic spines appear and disappear over days, whereas most spines are persistent for months(4-6,8,9). Under baseline conditions, new spines are mostly transient and rarely survive for more than a week. Transient spines tend to be small(4,5,9), whereas persistent spines are usually large(4-6,8,9). Because most excitatory synapses in the cortex occur on spines, and because synapse size(10) and the number of alpha-amino-3- hydroxy-5-methyl-4-isoxazole propionic acid ( AMPA) receptors(11-13) are proportional to spine volume, the excitation of pyramidal neurons is probably driven through synapses on persistent spines. Here we test whether the generation and loss of persistent spines are enhanced by novel sensory experience. We repeatedly imaged dendritic spines for one month after trimming alternate whiskers, a paradigm that induces adaptive functional changes in neocortical circuits(14,15). Whisker trimming stabilized new spines and destabilized previously persistent spines. New-persistent spines always formed synapses. They were preferentially added on L5B neurons with complex apical tufts rather than simple tufts. Our data indicate that novel sensory experience drives the stabilization of new spines on subclasses of cortical neurons. These synaptic changes probably underlie experience-dependent remodelling of specific neocortical circuits.