Neuron reconstruction using a Quantimet image analyzing computer system

A PDP-11/34 laboratory computer, a Quantimet image analyzer, and a research light microscope with motorized X, Y stage and focus axis are used for "semi-automatic" neuron reconstruction. The operator examines each neuron tree through the microscope eyepieces, commands the Quantimet system to move the stage and focus the optics, and when a point along the neuron process is in focus under a cross-hairs, commands the PDP-11 computer to record the point's spatial coordinate. A list of such coordinates when stored in the PDP-11 forms a mathematical reconstruction of the neuron. Because the Quantimet system was not designed for this type of work, there may arise some problems when using it. Incremental microscope stage movements are difficult to produce; its display does not accurately depict neurons; its software does not facilitate the simple commands to the microscope motors required in neuron reconstruction. Despite these constraints, a neuron tracing system has been written which traces and statistically analyzes neurons.