RESUMEN
In the present study the projections were traced from the red nucleus and the region of the griseum centrale mesencephali to the inferior olivary complex (IOC) by using the method of anterograde transport of the WGA-HRP in the cat. The results has led to the following conclusions: 1.Both injected regions have positive projections to the ipsilateral IOC. No labeled cells were found in the IOC. 2. The projections from the red nucleus to the IOC terminated in the dorsal lamina of the principal olive and the dorsal end of the caudal half of the medial accessory olive. The projections from the region of the griseum centrale mesencephali to the IOC terminated in the whole medial accessory olive, ventral lamina of the principal olive and the connecting part between the ventrolateral end of ventral lamina and dorsal lamina of the principal olive. The most heavily labeled regions were the dorsal lamina of the principal olive among the regions receiving projection from the red nucleus and the medial accessory olive among those receiving fibers from the griseum centrale mesencephali region, the other regions were more lightly labeled.3. Some labeled regions of the IOC in the present study overlapped with those regions receiving fibers from the spinal cord reported by others. In the present study the labeled area is more extensive than those reported in the literature.