The neuron doctrine is the theory stating that the brain is made up of many tiny individual unit cells, neurons, that are interconnected via networks, yet still separate entities.
Single cell staining by dye impregnation was the first and most influential circuit-mapping strategy. Employed by Santiago Ramon y Cajal (1852 - 1934), Golgi staining techniques (using potassium dichromate and silver nitrate) were used to stain neural networks. This 'black reaction' staining technique stains just a few individual cells at a time, in their entirety, including all processes. Cajal used it to stain networks and was subsequently able to discern the various types of neuronal networks in the brain, as well as describe their circuit organization.
We find several limitations with the single-cell staining techniques, however. They cannot effectively do long-distance traces, nor are they effective when processes come within 0.25um of each other (cannot see it in the light microscope). Researchers also have a difficult time distinguishing one cell from another, in some instances, if many elements in the same circuit are stained at once.
Mapping neural circuits is a central aim of modern neuroscience. We need to develop methods of labeling/imaging neurons because the behavior of neural networks is critical to brain function and dysfunction and we need to see how the neurons are connected to better understand the networks.
Single cell staining by dye impregnation was the first and most influential circuit-mapping strategy. Employed by Santiago Ramon y Cajal (1852 - 1934), Golgi staining techniques (using potassium dichromate and silver nitrate) were used to stain neural networks. This 'black reaction' staining technique stains just a few individual cells at a time, in their entirety, including all processes. Cajal used it to stain networks and was subsequently able to discern the various types of neuronal networks in the brain, as well as describe their circuit organization. We find several limitations with the single-cell staining techniques, however. They cannot effectively do long-distance traces, nor are they effective when processes come within 0.25um of each other (cannot see it in the light microscope). Researchers also have a difficult time distinguishing one cell from another, in some instances, if many elements in the same circuit are stained at once.
Mapping neural circuits is a central aim of modern neuroscience. We need to develop methods of labeling/imaging neurons because the behavior of neural networks is critical to brain function and dysfunction and we need to see how the neurons are connected to better understand the networks.
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