Visualization of Dendritic Spines

by Josef Spacek and John Fiala

Transmission Electron Microscopy

Until the era of electron microscopy, dendritic spines attracted little attention. They were even suspected of being an impregnation artefact. Gray (1959) showed them as real structures on which most synapses are located.

E. G. Gray 1959 Dendritic spines validated by electron microscopy

Rather than using light waves, the electron microscope passes electrons through a thin section of tissue. Photographs are made of the variations in electron density within the section. When the tissue has been properly stained, these patterns reveal the fine details of subcellular structures, down to a few nanometers.

The higher magnification of electron microscopy allowed detailed analysis of dendritic spines. In particular, it became possible to address questions of synaptic plasticity by using electron microscopy to evaluate the dimensions of dendritic spines and their synaptic contacts.

For a detailed look at some electron microscopic studies of dendrites see the various components of the Anatomy section of this website including the Atlas of Ultrastructural Neurocytology.

References

• Gray EG (1959) Electron microscopy of synaptic contacts on dendritic spines of the cerebral cortex. Nature 183:1592-1593.
• Gray EG (1959) Axo-somatic and axo-dendritic synapses of the cerebral cortex: an electron microscope study. J Anat 93:420-433.
• Peters A, Palay SL, Webster H (1991) The Fine Structure of the Nervous System. Third Edition. Oxford University Press: New York.

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