Morphometry of synapses on identified neurons in the visual cortex
Abstract
To illustrate the potentiality of morphometry in the study of identified neurons, a Golgi-impregnated, gold-toned neuron was thin sectioned and partly reconstructed. With this procedure the size distribution of synaptic contacts and their distribution along the neuronal surface could be determined. Both symmetrical and asymmetrical synapses were found on the cell body and dendrites. The total number of synapses encountered was 367 and the mean length was 400 nm. The completely reconstructed part of the neuron received 262 synapses. Thirty percent of the synapses were symmetrical and the other 70 percent asymmetrical, giving a total receptive surface of about 9 percent. Analysis of the distance of individual synapses from the centre of the cell revealed an even distribution along the neuronal surface, without a significant abundance on proximal or distal parts.