Developmental sculpting of dendritic morphology of layer 4 neurons in visual cortex: influence of retinal input.
Developmental sculpting of dendritic morphology of layer 4 neurons in visual cortex: influence of retinal input.
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DOI：
10.1523/jneurosci.5222-10.2011
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发表时间：
2011-05-18
期刊：
影响因子：
--
通讯作者：
Borrell V
中科院分区：
文献类型：
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作者：
Callaway EM;Borrell V
树突形态决定了神经元接收的输入类型，对神经信息处理产生深远的影响。在哺乳动物大脑皮层中，兴奋性神经元被归因于两种主要树突形态之一，锥体形或星形，其主要区别在于顶端树突的范围。人们已经研究了皮层锥体神经元调节树突形态的出现和细化的发育机制，但对多刺星状神经元知之甚少。使用生物射弹技术标记雪貂初级视觉皮层急性脑切片上的单细胞，我们发现第 4 层神经元的发育分两步过程：最初，所有神经元均呈锥体状，生长出突出的顶端树突和一些小的基底树突。随后，这些神经元中的大多数表现出基底树突和顶端树突的相对范围的变化，导致逐渐雕刻成星状形态。我们还发现，约 22% 的神经元保持其树突乔木的比例，在成熟时仍保留为锥体细胞。当雪貂在出生后发育的早期阶段通过双眼剜除术剥夺视网膜输入时，很大一部分第 4 层多刺神经元未能重塑其顶端树突，约 55% 仍保留为锥体神经元。我们的结果表明，皮层多刺星状神经元是通过对初始锥体形态的树突状树枝化进行差异雕刻而出现的，并且感觉输入在此过程中起着基本作用。
Dendritic morphology determines the kinds of input a neuron receives, having a profound impact on neural information processing. In the mammalian cerebral cortex, excitatory neurons have been ascribed to one of two main dendritic morphologies, either pyramidal or stellate, which differ mainly on the extent of the apical dendrite. Developmental mechanisms regulating the emergence and refinement of dendritic morphologies have been studied for cortical pyramidal neurons, but little is known for spiny stellate neurons. Using biolistics to label single cells on acute brain slices of the ferret primary visual cortex, we show that neurons in layer 4 develop in a two-step process: initially, all neurons appear pyramidal, growing a prominent apical dendrite and few small basal dendrites. Later, a majority of these neurons show a change in the relative extent of basal and apical dendrites that results in a gradual sculpting into a stellate morphology. We also find that ~22% of neurons maintain the proportionality of their dendritic arbors, remaining as pyramidal cells at maturity. When ferrets were deprived of retinal input at early stages of postnatal development by binocular enucleation, a significant proportion of layer 4 spiny neurons failed to remodel their apical dendrites, and ~55% remained as pyramidal neurons. Our results demonstrate that cortical spiny stellate neurons emerge by differential sculpting of the dendritic arborizations of an initial pyramidal morphology and that sensory input plays a fundamental role in this process.