The fine structure of synapses in relation to the large spherical neurons in the anterior ventral cochlear of the cat.

The fine structure of synapses in relation to the large spherical neurons, the principal neurons in the anterior ventral cochlear nucleus (AVCN) of the cat, was studied. Axo-somatic synapses were classified into three types based on their size and shape and the distribution of synaptic vesicles. Axo-dendritic synapses were also classified into three types with respect to synaptic contact, cytoplasmic densities associated with the pre- and postsynaptic membranes and the shape of the synaptic vesicles. Mossy fibre-like endings and preterminal axons containing dense-core vesicles were observed in this study. Serial or triadic synapses were also found in cat AVCN. We occasionally found a nematosome in the cytoplasm of the principal neuron.