PATTERN IN THE CORTICAL DISTRIBUTION OF PREFRONTALLY DIRECTED NEURONS WITH DIVERGENT AXONS IN THE RHESUS-MONKEY
PATTERN IN THE CORTICAL DISTRIBUTION OF PREFRONTALLY DIRECTED NEURONS WITH DIVERGENT AXONS IN THE RHESUS-MONKEY
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DOI：
10.1093/cercor/5.2.158
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发表时间：
1995-03-01
期刊：
影响因子：
3.7
通讯作者：
BARBAS, H
中科院分区：
文献类型：
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作者：
BARBAS, H
具有分叉轴突的神经元已经在几种结构中被注意到，但它们在皮层系统、皮层类型或皮层层中的组织尚不清楚。通过在恒河猴前额叶皮层的一个半球注射多种荧光逆行示踪剂来解决上述问题。前额叶皮层非常适合这项研究，因为它接收来自不同皮层系统的输入。少量神经元（约1%）投射到同侧前额叶的两个不同部位，因此被双重标记，在前额叶、前运动、视觉、体感、听觉和顶叶关联皮层中被注意到，表明这种形式的投射在皮层中是普遍存在的。然而，在移行区双标记神经元的数量明显高于终层区。此外，在过渡性和终层区，轴突分化的神经元在皮层深层比上层更普遍。尽管在一些成年哺乳动物物种中，具有不同轴突的神经元只占皮质-皮质投射的一小部分，但它们在胎儿或新生儿阶段的初级感觉皮层中占主导地位。过渡性脑区包含较多的轴突分化神经元，与终层感觉脑区相比，过渡性脑区可能在更大程度上保留了发育过程中观察到的一些特征。这有助于解释过渡性脑区巨大的可塑性及其与学习和记忆的关系，以及它们在阿尔茨海默病和癫痫等几种神经系统疾病中的优先脆弱性。
Neurons with divergent branched axons have been noted in several structures, but their organization across cortical systems, cortical types, or cortical layers is not known. The above questions were addressed with the aid of multiple fluorescent retrograde tracers injected in one hemisphere of the prefrontal cortex of rhesus monkeys. The prefrontal cortex is well suited for this study because it receives input from diverse cortical systems. A small number of neurons (similar to 1%) that projected to two different ipsilateral prefrontal sites, and were thus double-labeled, were noted in prefrontal, premotor, visual, somatosensory, auditory, and parietotemporal association cortices, suggesting that this form of projection is general within the cortex. However double-labeled neurons were noted in significantly higher numbers in transitional than in eulaminate areas. Moreover, neurons with divergent axons were more prevalent in the deep cortical layers than in the upper layers in both transitional and eulaminate areas. Although neurons with divergent axons constitute a small population of those that issue corticocortical projections in several adult mammalian species, they are preponderant in the primary sensory cortices of the fetal or neonatal stages. Transitional areas, which include a higher proportion of neurons with divergent axons, may retain some features observed in development to a greater extent than eulaminate sensory areas. This could help explain the great plasticity of transitional areas and their involvement in learning and memory, and also their preferential vulnerability in several neurologic disorders such as Alzheimer's disease and epilepsy.