Distribution and morphology of myelinated perikarya and dendrites in the olfactory bulb of primates

Numerous myelinated perikarya occur in different layers of the olfactory bulbs of a chimpanzee and two species of New World primates, that is, the squirrel and the Cebus monkey. It appears that somata of all established neuron categories, except for the mitral cells, can become ensheathed in myelin. Myelinated dendritic segments are found in the periglomerular region and in the external plexiform layer; tufted and periglomerular cells most likely to give rise to these myelinated dendrites. The myelin sheath is predominantly of the compact C.N.S. type. Perikaryal and dendritic myelin often ends in typical feet of glial cytoplasm. The termination site of dendritic myelin is a preferred site of synaptic contacts. Myelinated profiles are more numerous in the two monkey species than in the chimpanzee.