A Golgi study on the neuronal organization of the neostriatum in the mouse.
The neuronal organization of the neostriatum in mice was studied, using the rapid Golgi method. Based on the size of the somata, the neostriatal neurons were divided into groups of large, medium-sized and small cells, and the neurons of each group were further divided into 2-5 types, according to the shape of the somata and dendritic morphology. Three types of large neurons were recognized. Large type I neurons were triangular, piriform or fusiform cells with a few thick dendrites, whereas large type II and type III neurons were round or polygonal cells with numerous slender dendrites. The dendrites of the large type II neurons were far longer than those of large type III. Medium-sized neurons were grouped into 5 types. Medium type I neurons were round with spiny dendrites and were found mainly in the caudal portion of the neostriatum. Medium type II neurons had numerous thin dendrites and were predominant in the rostral portion of the neostriatum. Some medium type II neurons were arranged in cell chains extending perpendicular to Wilson's pencils. The cell bodies of medium type III neurons were triangular, and generated long spiny dendrites. Medium type IV neurons were polygonal, and dendrites with numerous short branchlets were evidenced. Medium type V neurons had poorly branched and sparsely spinous dendrites. The small neurons were of two types: small type I had piriform cell bodies, which gave rise to very thin dendrites, while small type II had dendrites with irregular contours and filiform appendages. Of these, the large type I and type II, the medium type I-V, and the small type I neurons seemed to be the projection neurons, whereas the large type III and small type II neurons were merely internuncials. Thus, the neostriatum in the mouse was shown to be composed of a wide variety of projection neurons and only two types of interneurons.
D000818:Animals; D001369:Axons / Q000032:analysis; D002421:Caudate Nucleus / Q000033:anatomy & histology / Q000166:cytology*; D051379:Mice; D009474:Neurons / Q000145:classification* / Q000166:cytology; D011699:Putamen / Q000033:anatomy & histology / Q000166:cytology*; D012834:Silver; D013194:Staining and Labeling
D012834:Silver