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Unbiased stereological estimation of the total number of synapses in a brain region

  • Published:
Journal of Neurocytology

Summary

Modern stereological methods have been used to make unbiased estimates of the total number of synapses in the striatum radiatum of the hippocampal CA1 region of five rabbits. The approach used involved a two stage analysis and is generally applicable to all parts of the nervous system. During the first stage of the analysis, the reference volume was estimated by point counting, at the light microscope level, according to the Cavalieri principle. During the second stage, the numerical density of synapses was estimated with disectors at the electron microscopic level. The total number of synapses was calculated as the product of the numerical density and the volume of the region. The sampling with points and disectors was carried out in all three dimensions of the entire CA1 region in a manner that ensured that all parts of the region and all synapses within it had equal probabilities of being sampled. An analysis of the precision of the estimate of total synapse number has been performed in terms of the variances of volume and synaptic numerical density at different levels of sampling, i.e. at the level of points, sections, individual animals and group of animals. Detailed descriptions of the procedures used to estimate the total number of synapses, evaluate the precision of the estimates, and optimize the sampling scheme are provided.

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Authors and Affiliations

  1. Department of Cell and Molecular Biology, Northwestern University Medical School, 303 East Chicago Avenue, 60611, Chicago, Illinois, USA

    Y. Geinisman & E. Van Der Zee

  2. Stereological Research Laboratory, University of Aarhus, 8000, Aarhus, Denmark

    H. J. G. Gundersen

  3. Institute for Neurobiology, University of Aarhus, 8000, Aarhus, Denmark

    M. J. West

Authors
  1. Y. Geinisman
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  2. H. J. G. Gundersen
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  3. E. Van Der Zee
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  4. M. J. West
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25th Anniversary Issue

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Geinisman, Y., Gundersen, H.J.G., Van Der Zee, E. et al. Unbiased stereological estimation of the total number of synapses in a brain region. J Neurocytol 25, 805–819 (1996). https://doi.org/10.1007/BF02284843

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