DEVELOPMENT OF SYNAPSES IN KITTEN VISUAL-CORTEX DURING VISUAL DEPRIVATION
DEVELOPMENT OF SYNAPSES IN KITTEN VISUAL-CORTEX DURING VISUAL DEPRIVATION
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DOI：
10.1016/0014-4886(75)90118-1
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发表时间：
1975-01-01
影响因子：
5.3
通讯作者：
CRAGG, BG
中科院分区：
文献类型：
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作者：
CRAGG, BG
突触发育对视觉功能的依赖性已经通过比较6只小猫与5只眼睑双侧缝合的小猫和2只视神经被压碎的小猫的对照组进行了测试。手术是在出生后的第一周进行的，然后所有的小猫都住在一个小房间里。当小猫45天大时，将大脑固定用于电子显微镜检查。视皮层深度扫描计数突触，冰冻切片光镜计数神经元胞体，缝合组和压碎组的平均神经元密度分别比对照组高28%和41%，而平均神经元直径减少8%或12%。在两个剥夺组中，在所有皮层深度的固定组织区域中的平均突触计数减少，但仅在软脑膜下1.0 - 1.4mm处有统计学意义的降低，达到22%。突触的估计密度（或单位体积的皮质柱中的数目）较低，但差异不显著，突触并置的平均长度也不变。突触密度除以神经元密度来估计与一个神经元相关的突触的平均数目，这在两个剥夺组中显著降低约30%。因此，完全失明对发育中的视觉皮层的影响并不比失去模式视觉大，而这两种形式的剥夺都会导致神经元连接的减少，而此时，视力正常的小猫的突触发育已经达到了一个平台期
The dependence of synaptic development on visual functioning has been tested by comparing a control group of 6 kittens with 5 kittens whose eyelids had been sutured bilaterally, and with 2 kittens whose optic nerves had been crushed. The operations were done during the first week after birth, and all the kittens then lived together in a small room. The brains were fixed for electron microscopy when the kittens were 45 days old. Synapses were counted in a depth scan of the visual cortex, and neuronal cell bodies were counted by light microscopy of frozen sections.The average neuronal densities were 28 or 41% higher in the sutured or crushed groups than in the controls, while average neuronal diameters were 8% or 12% less. The average count of synapses in a fixed area of tissue was decreased at all cortical depths in both deprived groups, but the decrease was statistically significant only between 1.0 and 1.4 mm below the pia, where it reached 22%. The estimated density of synapses (or number in a column of cortex of unit volume) was lower, but the difference was not significant, and the average length of synaptic apposition was also unchanged.Synaptic density was divided by neuronal density to estimate the average number of synapses associated with one neuron, and this was significantly depressed by about 30% in both deprived groups. Thus, complete blindness had little more effect on the developing visual cortex than loss of pattern vision, and both forms of deprivation led to reduced neuronal connectivity at a time when synaptic development has reached a plateau in sighted kittens