As neurophysiologists move away from topics of gross organization toward an interest in the finer details of cellular arrangement, it becomes necessary to describe the microscopic distribution of terminal fibers. Gross anatomical methods such as that of Marchi degeneration provide information only about gross connectivity, e.g., that a particular tract loses its myelin in a certain region and therefore probably terminates there. The beautiful Golgi technique tests the extremes of skill and patience of the anatomist. It is particularly difficult to use where the endings of long axons are being examined since the cell body of the axon cannot be seen and the exact origin of an axon cannot be known. However, such workers as Ramon y Cajal, Lorente de No, and Sholl have proved the extreme usefulness of the Golgi method. The recent modifications of the Bielschowsky technique by Nauta and Glees have revived interest in the degeneration method of finding endings. The future of this method seems hopeful but there are marked difficulties in technique and interpretation, particularly because of different results obtained by divers workers. It is also possible to use the conductive properties of nervous tissue to map connections. On the gross level of the Marchi method we have neuronography by strychnine and stimulation, the finding of evoked responses with minimum latency, etc. These tricks are useful for rapid plotting of rough connectivity but also produce their own special problems, some of which are mentioned in another paper.6 * Staff member. t Staff member. i Staff member. § Staff member
To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.