Tracing intrinsic fiber connections in postmortem human brain with WGA-HRP

Modern methods for tracing central nervous system pathways depend largely on active axonal transport mechanisms and are carried out in in vivo animal experiments. This report describes the ability to trace axons and label cell bodies in postmortem human material, using injections of wheat germ agglutinin horseradish peroxidase. Furthermore, it demonstrates the compatibility of this method with immunocytochemical techniques for localizing neurotransmitters. Thus it is possible to study the intrinsic circuitry or short connections in brain regions such as cortex in both normal and pathological material, and, using double label methods, determine the transmitter systems involved. It also raises the issue of the mechanisms which are involved in the movement of the tracer molecule.