[Demonstration of intrastriatal types of synapses and axon-collaterals by experimental isolation of fundus striati from all extrastriatal connections (author's transl)].

After columnar isolation of the cat's fundus striati with a survival time of 2 days or 2 or 4 weeks all axospinous boutons (type I, III And iv) and most axo-dendritic (or axo-somatic) boutons (type II, VI and VII) undergo dark degeneration. All specimens of axo-somatic (or axodendritic) type IX bouton (containing large, round vesicles in a clear axoplasm) and most specimens of type V bouton (with pleomorphic and some dense core vesicles) are unaltered. Many type VIII boutons (dindritic terminals containing scattered, small, sphrical vesicles suspended between the filaments of many microtubules in clear dendroplasm) are almost preserved, in the fundus more than in the caudate nucleus. After 2 or 4 weeks, some perikarya and many dendrites have undergone an electron-dense retrograde degeneration resulting from interuption of the efferent axons of the large striatal cells. The type IX synapses are interpreted as intrinsic between the small spiny and the large efferent striatal neurons; the type V as intrastriatal axon-collaterals of the large efferent neurons and the type VIII as dendritic terminals of intrastriatal Golgi type II nerve cells (possibly dwarf cells).