Anterograde and retrograde labelling of CNS pathways with unconjugated lectins using the unlabelled antibody enzyme method.

A method for demonstrating the anterograde and retrograde transport of unconjugated lectins in the CNS is given using the labelled antibody enzyme technique. Successful labelling of a variety of pathways is demonstrated using wheat germ agglutinin (WGA) and concanavalin A (Con A). Exceptionally large numbers of neurones labelled by retrograde transport were detected in each area. Using this method afferents to the mediodorsal thalamus are reported from prefrontal, cingulate and perirhinal cortex, substantia innominata, magnocellular and lateral preoptic area, ventral pallidum and diagonal band of Broca. In addition it is shown that large numbers of neurones of the periventricular hypothalamus and periaqueductal central grey of the mesencephalon techniques and further applications of the method are outlined.