Tract tracing involves injecting a tracer substance into a specific area of the nervous system. Depending on the type of tracer used, it can travel either anterogradely (from the cell body to the axon terminals) or retrogradely (from the axon terminals back to the cell body). Commonly used tracers include biotinylated dextran amine (BDA), Fluoro-Gold, and cholera toxin B (CTB). Once the tracer has traveled along the axons, tissue sections are prepared and examined under a microscope to visualize the labeled pathways.
