title: A single-neuron tracing study of arkypallidal and prototypic neurons in healthy rats.
abstract: The external globus pallidus (GP) is known as a relay nucleus of the indirect pathway of the basal ganglia. Recent studies in dopamine-depleted and healthy rats indicate that the GP comprises two main types of pallidofugal neurons: the so-called "prototypic" and "arkypallidal" neurons. However, the reconstruction of complete arkypallidal neurons in healthy rats has not been reported. Here we visualized the entire axonal arborization of four single arkypallidal neurons and six single prototypic neurons in rat brain using labeling with a viral vector expressing membrane-targeted green fluorescent protein and examined the distribution of axon boutons in the target nuclei. Results revealed that not only the arkypallidal neurons but nearly all of the prototypic neurons projected to the striatum with numerous axon varicosities. Thus, the striatum is a major target nucleus for pallidal neurons. Arkypallidal and prototypic GP neurons located in the calbindin-positive and calbindin-negative regions mainly projected to the corresponding positive and negative regions in the striatum. Because the GP and striatum calbindin staining patterns reflect the topographic organization of the striatopallidal projection, the striatal neurons in the sensorimotor and associative regions constitute the reciprocal connection with the GP neurons in the corresponding regions.
authors.affiliation: Laboratory of Neural Circuitry, Graduate School of Brain Science, Doshisha University, Kyotanabe, Kyoto, 619-0394, Japan. ffujiyam@mail.doshisha.ac.jp.|CREST, JST, Saitama, 332-0012, Japan. ffujiyam@mail.doshisha.ac.jp.
authors.forename: Fumino
authors.initials: F
authors.lastname: Fujiyama
authors.affiliation: Department of Anatomy, Shiga University of Medical Science, Shiga, 520-2121, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Nakano
authors.affiliation: Department of Morphological Brain Science, Graduate School of Medicine, Kyoto University, Kyoto, 606-8501, Japan.
authors.forename: Wakoto
authors.initials: W
authors.lastname: Matsuda
authors.affiliation: Department of Morphological Brain Science, Graduate School of Medicine, Kyoto University, Kyoto, 606-8501, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Furuta
authors.affiliation: Department of Anatomy, Shiga University of Medical Science, Shiga, 520-2121, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Udagawa
authors.affiliation: Department of Morphological Brain Science, Graduate School of Medicine, Kyoto University, Kyoto, 606-8501, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kaneko
mesh_terms: D000818:Animals; D001369:Axons; D001921:Brain / Q000166:cytology*; D003342:Corpus Striatum / Q000166:cytology; D020392:Entopeduncular Nucleus / Q000166:cytology; D005822:Genetic Vectors; D005917:Globus Pallidus / Q000166:cytology*; D049452:Green Fluorescent Proteins / Q000008:administration & dosage; D008297:Male; D009434:Neural Pathways / Q000166:cytology; D056347:Neuroanatomical Tract-Tracing Techniques; D009474:Neurons / Q000166:cytology*; D017729:Presynaptic Terminals; D051381:Rats; D017208:Rats, Wistar; D013378:Substantia Nigra / Q000166:cytology; D020531:Subthalamic Nucleus / Q000166:cytology
chemical_list: D049452:Green Fluorescent Proteins
keywords: Arkypallidal neuron; Basal ganglia; Globus pallidus; Prototypic neuron; Single neuron tracing; Striatum