The development of commissural connections of somatic motor-sensory areas of neocortex in the North American opossum.
The development of commissural connections of somatic motor-sensory areas of neocortex in the North American opossum.
复制标题
北美负鼠新皮质体细胞运动感觉区连合连接的发展。
DOI：
10.1007/bf00319061
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发表时间：
1985
期刊：
影响因子：
--
通讯作者：
Martin,GF
中科院分区：
文献类型：
--
作者：
Cabana,T;Martin,GF
北美负鼠没有胼胝体；新皮质连合轴突完全包含在前连合内。我们使用轴突运输技术来研究发育中和成年负鼠体细胞运动感觉皮层连合轴突的起源和分布。新皮质轴突在出生后（PND）12天长入前连合，在约PND 19时长入对侧外囊，在约PND 26时长入对侧同型皮层深处，在约PND 35时长入固有皮层。连合神经元在约PND 26时首次被证实，当时它们在皮质底板（假定的层V-VI）中形成相当连续的带。至少到 PND 37 时，连合神经元也出现在第 II 层和第 III 层中，在这些层中它们形成连续带，在第 IV 层中也存在，它们在这些层中是稀疏的。在年长的育儿袋中，年轻和成年负鼠的连合神经元带，特别是在 V-VI 层中，被中断，而连合神经元在 IV 层中很少见。一般来说，幼年负鼠和成年负鼠的连合轴突都支配含有连合神经元和第一层的区域。在无胼胝体负鼠和胼胝体大鼠中，体细胞运动感觉皮层的连合连接的发展特点是轴突生长到相反皮层期间的暂停，一般由内而外的梯度，以及从连续带到斑片状径向柱的过渡。连合神经元和轴突。这表明相似的机制控制着两个物种连合连接的形成。
The North American opossum does not have a corpus callosum; neocortical commissural axons are contained entirely within the anterior commissure. We have used axonal transport techniques to study the origin and distribution of commissural axons from somatic motor-sensory cortex in developing and adult opossums. Neocortical axons grow into the anterior commissure by postnatal day (PND) 12, the contralateral external capsule by approximately PND 19, the area deep to the contralateral homotypic cortex by approximately PND 26 and the cortex proper by approximately PND 35. Commissural neurons were first demonstrated at about PND 26, when they form a fairly continuous band in the cortical subplate (presumptive layers V–VI). By at least PND 37, commissural neurons are also present in layers II and III, where they form a continuous band, and in layer IV, where they are sparse. In older pouch young and adult opossums the bands of commissural neurons, especially in layers V–VI, are interrupted, and commissural neurons are rare in layer IV. In general, commissural axons in both pouch-young and adult opossums innervate areas containing commissural neurons as well as layer I.In the acallosal opossum as well as in the callosal rat, the development of commissural connections from somatic motor-sensory cortex is characterized by pauses during the growth of axons into the opposite cortex, by a general inside-out-gradient, and by a transition from continuous bands to patchy, radial columns of commissural neurons and axons. This suggests that similar mechanisms govern the formation of commissural connections in the two species.