An On-Line Digital-Computer System for the Semiautomatic Analysis of Golgi-Impregnated Neurons

Rapid and accurate measurements of neuronal processes in Golgi preparations are possible with the aid of a small computer (Glaser and Van der Loos, 1965). This paper describes a system for doing this, using a small digital computer which controls stepping motors (0.5-μm steps) attached to the stage (x, y axes) and fine focus (z axis) of a microscope. The observer tracks the processes, topological information, such as the location of the soma, dendritic origins, branch points, and ends of processes, is signaled to the computer by special controls, and the x, y, and z coordinates of each are stored in digital format. The computer printout yields 1) individual x, y, and z coordinates with associated topological identifiers; 2) quantitative data for each dendritic segment in order (i.e., primary and secondary branches, etc.); and 3) computes the actual linear dimensions of each segment in microns. An associated oscilloscope display can 1) display the whole neuron, or individual processes, by connecting recorded points by vectors; 2) identify each dendrite; 3) rotate (continuously or by a specified angle) the whole cell, or individual dendrites, around any selected point or axis; and 4) indicate spatial relationships by dynamic rotation, intensity modulation, or stereo pairs. The performance of this system has been evaluated for accuracy and the repeatability of measurements.