| Abstract: | The nucleus of the phrenic nerve on the ipsilateral side of segments C4–C6 of the cat spinal cord was localized by the retrograde degeneration method. The nucleus was reconstructed from a series of transverse sections and it was identified with the latero-medial nucleus of Rexed's lamina IX. The structure of the phrenic nucleus was described on the basis of a series of sections cut in three mutually perdendicular sections of the spinal cord. The nucleus consists of neuron groups the intervals between which are filled with bands of closely packed dendrites. Each group contains a set of various types of neurons and, in particular, from 5 to 7 motoneurons. Approximately 30 groups can be counted in the phrenic nucleus. It is postulated that the respiratory center may utilize this structure of the phrenic nucleus for the effective control of its level of activity.Institute of Problems of Information Transmission, Academy of Sciences of the USSR, Moscow. Translated from Neirofiziologiya, Vol. 6, No. 5, pp. 513–518, September–October, 1974. |
