Fig. 12.3. An oligodendrocyte adjacent to a neuron in layer 5 of the visual cortex in a 35 year old monkey. Oligodendrocytes in satellite locations are not infrequent and are sometimes regarded as a subset of the oligodendrocytic population. Small dark patches (arrows) are commonly seen along the interface between the oligodendrocytes and neurons, and these patches appear to be primitive junctional zones.