Short Axon Neuronal Subsystems In The Visual Cortex of The Monkey

Abstract

In seeking for a functional schema of the organization of the visual centers, we have studied with the Golgi method the varieties and connections of short-axon cells and other related neurons in the middle layers of the striate area in the adult monkey. Short-axon cells in layer IV have been classified into stellate cells with recurrent ascending axons ending in layers III and IVa, and clewed cells with characteristic axonal nets localized in their own dendritic field. Short-axon cells have been found in clusters or glomeruli upon which terminal branches of cortical afferents have been observed. It is suggested that periglomerular stellate cells with ascending axons connect clusters of clewed cells with small, medium and large stellate and pyramidal cells of layers III and IVa, which in turn would activate the giant solitary cells of layer V through synaptic contacts along vertical descending axons. Two levels of cortical afferent ramifications in layers III and IVc have been identified. Their morphological characteristics have been described.