Fig. 2.

One-dimensional neuroanatomical tracing: a anterograde tracing. Tracers such as PHA-L, BDA, RDA, Biocytin, or WGA-HRP injected in nucleus ‘A’ label complete efferent fiber trajectories including axon terminals in nucleus ‘B’. Neurons in nucleus ‘A’ are labeled irrespective of their neurochemical phenotype. In the injection site projection, neurons and interneurons both become labeled and are indistinguishable from each other. WGA-HRP and BDA are to some degree retrogradely transported (indicated here as granules in the first-order neurons in nucleus ‘B’). b Retrograde tracing. Compounds such as Fluoro-Gold, CTB, RV, and PRV label projection neurons irrespective of their neurochemical phenotype