The structure of chicken ectostriatum. I. Golgi study.

Chicken ectostriatum was studied in Golgi preparations. In the two parts of the area (ectostriatum centrale and ectostriatum periphericum) the cell types were analysed. Projection neurons with long axon, and interneurons with short axon, could be distinguished in both parts of the region. The projection neurons are different in the two parts of the area, whilst the interneurons, with regard to their morphological features, are completely similar. The stellate-like projection neurons in ectostriatum centrale have 4-6 main dendrites, which ramify only slightly, and are densely covered by characteristic spines. The projection neurons in ectostriatum periphericum emit several (7-10) main dendrites, which have numerous bifurcations establishing a dense dendritic tree. The dendrites are densely covered by regular spines. The interneurons--in both parts of ectostriatum--have three subtypes. All have characteristic local axonal arborizations with varicose terminal sections. Some quantitative parameters of Golgi impregnated neurons were also measured and analysed by computer. Preliminary results of this study are included in the present publication.