Location of dorsal interosseus motor nuclei in the cat

In the cat we have investigated the position of the motor nuclei projecting through the dorsal interosseus nerve to the distal forelimb muscles. Horseradish peroxidase was either injected into single muscles or applied to the central end of a cut nerve. The location of each nucleus is described in two ways: histograms giving the distribution of the labelled motoneurones along the rostro-caudal spinal cord axis; and regions in reconstructed cross-sections of the ventral horn which indicate the area occupied by the motoneurones of one nucleus. The relation between the nuclei was established by superposition of the reconstructed cross-sections. With this procedure we have obtained a map which shows the positions of the centres of the single radial nuclei.