Complementary mosaic distributions of thalamic and nigral axons in the caudate nucleus of the cat: double anterograde labeling combining autoradiography and wheat germ-HRP histochemistry.

The discontinuous terminal distributions of thalamo- and nigrostriatal axons were examined in adjacent tissue sections from single cat brains by combined anterograde labeling with tritiated proline autoradiography and wheat germ-horseradish peroxidase histochemistry. Injection of one tracer into the centromedian-parafascicular complex of the thalamus and the other into the substantia nigra reveals that, to a large extent, the patches of high density terminations within the caudate nucleus from these two structures interdigitate with each other in a complementary pattern.