Biocytin is widely used in neuroscience research as a neuronal tracer. It is particularly valuable for labeling and visualizing neurons due to its ability to diffuse through intracellular spaces and form stable complexes with avidin or streptavidin, which can then be detected using fluorescence or enzymatic methods. This property makes it an essential tool for mapping neural circuits, studying synaptic connections, and understanding the morphology of neurons. Additionally, biocytin is often employed in electrophysiological studies to mark recorded cells, allowing researchers to correlate functional data with structural information. Its compatibility with various staining and imaging techniques further enhances its utility in detailed neuroanatomical studies.