Tracing axons and axon collaterals of spinal neurons using intracellular injection of horseradish peroxidase.

Intracellular injection and subsequent histochemical localization of horseradish peroxidase have been used to stain the soma, dendrites, axons, and axon collaterals of spinalcervical tract neurons and unidentified dorsal horn neurons in the cat. This technique may be used in combination with the intracellular injection of Procion yellow to demonstrate by light microscopy connections between physiologically typed vertebrate neurons.