Visualization of Dendritic Spines

by Josef Spacek and John Fiala

Serial Section Electron Microscopy and Three-Dimensional Reconstruction

To overcome the limitations of the inherent two-dimensional nature of electron microscopy, sections can be cut serially from a tissue block. Each section contains a portion of the original structure that can be separately imaged with transmission electron microscopy. The problem then becomes how to reconstruct the three-dimensional structure from these section images.

A ribbon of serial sections from the ultramicrotome.

In the pre-computer era, tracings of sectioned objects were transferred to physical material and assembled, or graphically drawn by hand. Now mostly computer-assisted reconstructions are produced, like the ones in this website, which were produced with the aid of the software developed in our laboratory (see Synapse Web Tools).

A realigned stack of serial section electron micrographs reconstructs a volume of neuropil from the hippocampus. Within this volume 10 segments of spiny dendrites of CA1 pyramidal cells have been traced and computer rendered to reveal their three-dimensional relationships. (Click on image to see rendered dendrites.)

References

• Spacek J (1971) Three-dimensional reconstructions of astroglia and oligodendroglia cells. Z Zellforsch Mikrosk Anat. 112:430-442.
• Spacek J, Lieberman AR (1974) Three-dimensional reconstruction in electron microscopy of the central nervous system. Sbor.ved. praci Hradec Kralove 17:203-222.
• Spacek J, Hartmann M (1983) Three-dimensional analysis of dendritic spines. I. Quantitative observations related to dendritic spine and synaptic morphology in cerebral and cerebellar cortices. Anat. Embryol. 167:289-310.
• Harris KM, Stevens JK (1988) Study of dendritic spines by serial electron microscopy and three-dimensional reconstructions. In: Intrinsic determinants of neuronal form and function. Neurology and Neurobiology Volume 37 (Lasek RJ, Black MM eds), pp 179-199. New York: Alan R. Liss.
• Harris KM (1994) Serial electron microscopy as an alternative or complement to confocal microscopy for the study of synapses and dendritic spines in the central nervous system. In: Three-dimensional confocal microscopy: volume investigation of biological specimens (Stevens JK, Mills LR, Trogadis JE eds), pp 421-445. New York: Academic Press, Inc.
• Fiala JC, Harris KM (2001) Extending unbiased stereology of brain ultrastructure to three-dimensional volumes. Journal of the American Medical Informatics Association. 8(1):1-16. (Offprint 727K PDF)
• Fiala JC, Harris KM (2002) Computer-based alignment and reconstruction of serial sections. Microscopy and Analysis. USA Edition. 52:5-7. (Preprint 414K PDF)
• Fiala JC (2002) Three-dimensional structure of synapses in the brain and on the web. Proceedings of the 2002 International Joint Conference on Neural Networks, May 12-17, Honolulu, Hawaii, pp. 1-4. (469K PDF)

Top

Next installment: Filled Cells