A procedure for sampling specific portions of identified neurons for ultrastructural examination

A procedure is described which facilitates the ultrastructural examination of selected regions of a neuron identified because it is Golgi-impregnated or HRP-filled. The procedure involves assigning a two-dimensional coordinate to every point on a drawing of the neuron by superimposing a grid over the drawing. A complete series of thick sections through the block containing the identified cells can then be related to each point on the drawn cell. A thick section which contains a region of interest is remounted on a plastic blank. From this new block one obtains thin sections for ultrastructural examination.