SYNAPTOGENESIS IN THE PREFRONTAL CORTEX OF RHESUS-MONKEYS
SYNAPTOGENESIS IN THE PREFRONTAL CORTEX OF RHESUS-MONKEYS
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DOI：
10.1093/cercor/4.1.78
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发表时间：
1994-01-01
期刊：
影响因子：
3.7
通讯作者：
RAKIC, P
中科院分区：
文献类型：
--
作者：
BOURGEOIS, JP;GOLDMANRAKIC, PS;RAKIC, P
自世纪以来，大脑皮层的前额叶联合区一直被认为是皮层外套膜最后发育的区域之一。我们用定量电镜分析方法研究了25只猕猴前额叶皮层突触发生的过程，年龄从胚胎47天（E47）到20岁。一系列覆盖每只动物整个皮层厚度的重叠电子显微照片提供了关于神经元单位面积（N-A）和单位体积（N-V）突触的数量、比例和密度的数据。前额叶皮层中突触形成的克里思和动力学与感觉和运动区中描述的非常相似，特别是在突触获得和过度产生的阶段（Rakic等，1986年）。在年轻的胚胎中，我们描述了一个皮质前阶段（E47-E78），当突触被发现只有上面和下面，但没有内，皮质板。在此之后，有一个早期皮质阶段，从E78到E104，在此期间，突触在皮质板内积累，最初仅在树突轴上。下一个突触发生的快速阶段开始于出生前2个月，大约在出生后2个月结束，最终达到每立方微米7.5亿个突触的平均密度。这种积累在很大程度上是由选择性增加轴棘突触在颗粒层。爆发性突触密度期之后是一个延长的平台期，持续2个月至3岁，此时突触密度保持相对恒定。下降的最后一个时期，从3岁到20岁以上，是由轻微的，但统计学上显着的突触density. Concurrentrecruitment的下降与感觉和运动区的突触支持的概念，即最初建立的皮层电路是由共同的al区域，独立于其特定的功能域的一般机制。从青春期早期到青春期（高原期），突触密度相对稳定，这一发现表明，在灵长类动物中，在学习经历最强烈的形成期，突触密度保持一致和高的重要性。
Since the turn of the century, the prefrontal association areas of the cerebral cortex have been thought to be among the last regions of the cortical mantle to develop, We have examined the course of synaptogenesis in the macaque prefrontal cortex by quantitative electron microscopic analysis in 25 rhesus monkeys ranging in age from embryonic day 47 (E47) to 20 years of age. A series of overlapping electron micrographs spanning the whole cortical thickness in each animal provided data on the number, the proportion, and the density of synapses per unit area (N-A) and per unit volume (N-V) of neuropil.The tempo and kinetics of synapse formation in prefrontal cortex closely resemble those described for sensory and motor areas, particularly during the stages of synapse acquisition and overproduction (Rakic et al., 1986). In young embryos, we describe a precortical phase (E47-E78), when synapses are found only above and below, but not within, the cortical plate. Following that, there is an early cortical phase, from E78 to E104, during which synapses accumulate within the cortical plate, initially exclusively on dendritic shafts. The next rapid phase of synaptogenesis begins at 2 months before birth and ends approximately at 2 months after birth, culminating with a mean density of 750 million synapses per cubic micrometer. This accumulation is largely accounted for by a selective increase in axospine synapses in the supragranular layers. The period of explosive synaptic density is followed by a protracted plateau stage that lasts from 2 months to 3 years of age when synaptic density remains relatively constant. The final period of decline, from 3 years through over 20 years of age, is marked by a slight but statistically significant decline in synaptic density.Concurrent recruitment of synapses with that of sensory and motor areas supports the concept that the initial establishment of cortical circuitry is governed by general mechanisms common to al areas, independent of their specific functional domain. The finding that synaptic density is relatively stable from early adolescence through puberty (the plateau period) is indicative of the importance, in primates, of a consistent and high synaptic density during the formative years when learning experiences are most intense.