Rubrospinal tract in the Formosan monkey: HRP and autoradiographic studies.

Neurons projecting from the red nucleus to the spinal cord in the Formosan monkey were identified with retrograde horseradish peroxidase and tritiated proline and fucose antegrade autoradiographic tracing methods. A topographic organization of projections from the red nucleus to the spinal cord was demonstrated. Medial and dorsal portions of the rostral red nucleus projected to the rostral half of the spinal cord. Neurons in the ventrolateral part of the red nucleus emitted fibers which terminated in the caudal half of the spinal cord. The spinal projections from the red nucleus are bilateral, but contralateral projection is dominant. These results indicated a well developed rubrospinal tract existence in the Formosan monkey.