[Cytoarchitecture of the olfactory bulb of the rat]

The olfactory tubercle of rat was investigated by means of the rapid Golgi impregnation procedure. Based on morphological criteria, seven neuron types can be distinguished in this brain region of adult rat. Two types (pyramidal neurons and large polygonal neurons) are considered to be efferent in nature whereas the other types (spine-bearing fusiform neurons; aspiny fusiform neurons; granule cells; dwarf neurons, and neuroglioform neurons) do, in all probability, represent tuberculum interneurons. It is obvious from impregnation studies done in the olfactory tubercle of very young rats (seven days postsnatally) that neurons are still poorly differentiated at this time.