[Light microscopic and ultrastructural study of the lower olivary complex in the pigeon (Columba livia)]

The normal morphology of neurones and neuropile of the inferior olivary complex (LOC) in a pigeon (Columbia livia) was investigated by a light and electron microscope. The light microscopic analysis on the basis of the histological techniques of Vissl, Gldgi-Rio Hortega showed that olivary neurons had moderate mean dimensions and moderately branched dendrite tree, but single neurons with a model for dendrite branches were encountered similar to the second type of neurons in mammals. Axo-somatic synapses and synapses on the primary dendrites were comparatively small in number, observed by the electron microscope. Complex synaptic connections, similar to those of the mammals, were observed in the neuropile of LOC together with axo-dendrite synapses. The central part of glomerulo-like connections consisted of two-three dendrite profiles, connected sometimes with desmosomelike contacts. The presented results show that the morphological characteristics of olivary neurons of a pigeon are similar to those of mammals, although they are not so complex.