Elsevier

Brain Research

Volume 6, Issue 4, December 1967, Pages 716-727
Brain Research

The formation of synaptic junctions in developing rat brain: A quantitative electron microscopic study

https://doi.org/10.1016/0006-8993(67)90128-XGet rights and content

Abstract

The formation of synaptic junctions in developing rat brain has been studied with the electron microscope, utilizing a selective staining method. In this procedure, glutaraldehyde-fixed tissue is not exposed to osmium tetroxide, but instead is blockstained with phosphotungstic acid in solution of ethanol. A selective staining of the paramembranous components of synaptic junctions results from this treatment, thus facilitating a quantification of the numerical density of synaptic junctions over large areas of sections.

It was found that a sharp increase in the number of synaptic junctions occurs in rat cortex (molecular layer) during the 3rd and 4th postnatal weeks. The relationship between this increase in the numerical density of synaptic junctions and other events during development, such as the maturation of the EEG, is discussed. In addition, it is proposed that synaptic junctions evolve through several stages and a tentative morphogenetic scheme is presented.

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