Single subthalamic nucleus neurons project to both the globus pallidus and substantia nigra in rat.
The organization of the major efferents of the rat subthalamic nucleus (STN) was investigated using a fluorescent retrograde double-labeling technique. Red fluorescent Evans Blue was injected into the globus pallidus and blue fluorescent DAPI-Primuline was injected into the substantia nigra. After retrograde axonal transport many double-labeled neurons were seen throughout the STN. Occasionaly double-labeled cells were seen in the lateral hypothalamus just medial to the STN and in a thin lateral strip of neurons extending laterally from the STN. Evidence for a mediolateral topography in both the STN-pallidal and STN-nigral pathways was obtained. The STN contains few, if any, local interneurons. Cell counts revealed that at least 94% of, and possibly all, STN neurons send axon collaterals to both the globus pallidus and substantia nigra.
D000818:Animals; D001369:Axons / Q000648:ultrastructure; D004525:Efferent Pathways / Q000033:anatomy & histology; D005917:Globus Pallidus / Q000033:anatomy & histology*; D008297:Male; D009474:Neurons / Q000648:ultrastructure; D051381:Rats; D013378:Substantia Nigra / Q000033:anatomy & histology*; D013787:Thalamic Nuclei / Q000033:anatomy & histology*