Intracortical termination of the retino-geniculo-striate pathway studied with transsynaptic tracer (wheat germ agglutinin-horseradish peroxidase) and cytochrome oxidase staining in the macaque monkey.

The tracer, wheat germ agglutinin conjugated to horseradish peroxidase (WGA-HRP), was used as a transneuronal marker in the macaque monkey to study retino-geniculo-striate pathway terminals in area 17. Concomitantly, we stained matching sections for metabolic capacity using the cytochrome oxidase staining technique. Terminal labeling by WGA-HRP and cytochrome oxidase activity staining revealed duplicate patterns in layers II and III, IVA, IVC alpha, IVC beta, and VI. The absence of WGA-HRP-labeled neuronal cell bodies in area 17 supports the conclusion that WGA-HRP is a transsynaptic marker in the macaque visual pathways.