Monosynaptic projection from the pedunculopontine tegmental nuclear region to the reticulospinal neurons of the medulla oblongata. An electron microscope study in the cat.

The magnocellular reticular nucleus (MRN) of the cat was observed electron microscopically following the combined application of kainic acid into the pedunculopontine tegmental nuclear region (PPN region) and horseradish peroxidase conjugated to wheat germ agglutinin (WGA-HRP) into the spinal cord. Some degenerating axon terminals arising from the PPN region were found to make synaptic contacts with retrogradely HRP-labeled reticulospinal neurons in the MRN.