Structural basis for map formation in the thalamocortical pathway of the barrelless mouse
Structural basis for map formation in the thalamocortical pathway of the barrelless mouse
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DOI：
10.1523/jneurosci.1263-06.2006
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发表时间：
2006-09-27
影响因子：
5.3
通讯作者：
Welker, Egbert
中科院分区：
文献类型：
--
作者：
Gheorghita, Fulvia;Kraftsik, Rudolf;Welker, Egbert
无桶小鼠（BRL）的BRL突变，破坏了11号染色体上的腺苷酸环化酶I型编码基因的纯合子缺乏空间分离的第四层皮质细胞和丘脑皮质轴突（TCA）到桶域。尽管有这些形态上的扰动，功能地形图已被证明。我们从NOR（正常）和BRL小鼠的丘脑桶皮质重建了单独的生物细胞素注射的TCA，以分析TCA树枝化模式和bouton分布在多大程度上可以解释胡须卵泡的地形图表示。在BRL中，TCA的几何形状在第IV层内以及在晶下层中被修改。然而，在这两个菌株中，TCA在IV层的空间分布反映了它们的丘脑腹侧基底核中的细胞体的空间关系。形态计量学分析显示，两种菌株的TCA具有相同的长度，分支数量，和轴突终扣的数量在第四层。然而，在无桶，钮子分布在一个更大的切线范围内。从相邻的丘脑神经元的终扣的分布分析表明，存在于IV层的高终扣密度的域，在这两个菌株等于个别桶的大小和形状。我们建议，高终子密度的领域是在无桶小鼠的触须地图的基础上。
Barrelless mice (BRL) homozygous for the BRL mutation that disrupts the gene coding for adenylyl cyclase type I on chromosome 11 lack spatial segregation of layer IV cortical cells and of the thalamocortical axons (TCAs) into barrel domains. Despite these morphological perturbations, a functional topographic map has been demonstrated. We reconstructed individual biocytin-injected TCAs from thalamusto barrel cortex in NOR (normal) andBRLmice to analyze to what extent the TCA arborization pattern and bouton distribution could explain the topographic representation of the whisker follicles. In BRL, the geometry of TCA is modified within layer IV as well as in infragranular layers. However, in both strains, the spatial distribution of TCA in layer IV reflects the spatial relationship of their cell bodies in the ventrobasal nucleus of the thalamus. The morphometric analysis revealed that TCAs of both strains have the same length, branch number, and number of axonal boutons in layer IV. However, in barrelless, the boutons are distributed within a larger tangential extent. Analysis of the distribution of boutons from neighboring thalamic neurons demonstrated the existence in layer IV of domains of high bouton density that in both strains equal the size and shape of individual barrels. We propose that the domains of high bouton density are at the basis of the whisker map in barrelless mice.