O'Kusky J, Colonnier M
J Comp Neurol. 1982 Sep 20;210(3):291-306. doi: 10.1002/cne.902100308.
The surface area of the striate cortex and the thickness of its laminae were measured in a series of newborn, 3-month, 6-month, and adult macaque monkeys. The numerical densities (Nv) of neurons and synapses were measured in individual laminae. The total numbers of neurons and synapses in the striate cortex of one hemisphere were derived from these measures. Normal monkeys were compared at 3 months and 6 months of age to animals having been reared from birth with a monocular eyelid suture. No significant differences were observed between normal and monocularly deprived monkeys. The perceptual deficits and physiological abnormalities that have been reported in monocularly deprived monkeys do not appear to result from a reduction in the amount of neural circuitry in the striate cortex. The combined data from these groups, however, demonstrated several developmental changes. Cortical thickness increased from birth to 6 months and diminished to near-newborn values in the adult. The 6-month cortex was 19% thicker than that of the adult. This overshoot was greatest in layers II and III, which were 43% thicker at 6 months. Cortical surface area demonstrated a similar trend, being 23% greater at 6 months, but the differences were not statistically significant. The Nv of neurons decreased from birth to 6 months and increased to near-newborn values in the adult. The 6-month Nv was 30% less than that of adults and the greatest changes were seen in layers II and III where the Nv was 38% less than adult values. The total number of neurons in the striate cortex of one hemisphere was 16% less in adults than in newborn animals, but statistically significant neuron losses were limited to layers I, II, IVC alpha, V, and VI. The Nv of synapses increased from birth to 6 months and diminished to near-newborn values in the adult. The 6-month overshoot was 34% for the total cortex and 41% for layers I-III. The total number of synapses in the striate cortex was 95% greater at 6 months than in the adult. In layers I-III the synapses were 130-155% more numerous at 6 months. These data demonstrate an increase in neuronal connectivity in the striate cortex from birth to 6 months, especially in layers I-III, and a subsequent decrease in the adult.
在一系列新生、3个月、6个月和成年猕猴中测量了纹状皮层的表面积及其各层的厚度。在各个层中测量了神经元和突触的数值密度（Nv）。从这些测量值得出一个半球纹状皮层中神经元和突触的总数。将3个月和6个月大的正常猴子与从出生就单眼眼睑缝合饲养的动物进行比较。在正常猴子和单眼剥夺猴子之间未观察到显著差异。在单眼剥夺猴子中所报道的感知缺陷和生理异常似乎并非由纹状皮层中神经回路数量的减少所致。然而，这些组的综合数据显示了一些发育变化。皮层厚度从出生到6个月增加，在成年时减少到接近新生时的值。6个月大时的皮层比成年时厚19%。这种超量在第II层和第III层最为明显，6个月时这两层比成年时厚43%。皮层表面积呈现类似趋势，6个月时比成年时大23%，但差异无统计学意义。神经元的Nv从出生到6个月减少，在成年时增加到接近新生时的值。6个月时的Nv比成年时少30%，最大变化见于第II层和第III层，那里的Nv比成年值少38%。一个半球纹状皮层中神经元的总数在成年时比新生动物少16%，但有统计学意义的神经元损失仅限于第I层、第II层、第IVCα层、第V层和第VI层。突触的Nv从出生到6个月增加，在成年时减少到接近新生时的值。整个皮层在6个月时的超量为34%，第I - III层为41%。纹状皮层中突触的总数在6个月时比成年时多95%。在第I - III层，6个月时突触数量多130 - 155%。这些数据表明，从出生到6个月，纹状皮层中神经元的连接性增加，尤其是在第I - III层，而在成年后则减少。
