title: Thalamic innervation of the direct and indirect basal ganglia pathways in the rat: Ipsi- and contralateral projections.
abstract: The present study describes the thalamic innervation coming from the rat parafascicular nucleus (PF) onto striatal and subthalamic efferent neurons projecting either to the globus pallidus (GP) or to the substantia nigra pars reticulata (SNr) by using a protocol for multiple neuroanatomical tracing. Both striatofugal neurons targeting the ipsilateral SNr (direct pathway) as well as striatal efferent neurons projecting to the ipsilateral GP (indirect pathway) were located within the terminal fields of the thalamostriatal afferents. In the subthalamic nucleus (STN), both neurons projecting to ipsilateral GP as well as neurons projecting to ipsilateral SNr also appear to receive thalamic afferents. Although the projections linking the caudal intralaminar nuclei with the ipsilateral striatum and STN are far more prominent, we also noticed that thalamic axons could gain access to the contralateral STN. Furthermore, a small number of STN neurons were seen to project to both the contralateral GP and PF nuclei. These ipsi- and contralateral projections enable the caudal intralaminar nuclei to modulate the activity of both the direct and the indirect pathway.
authors.affiliation: Department of Anatomy, Division of Neurosciences, Clínica Universitaria and Medical School, Center for Applied Medical Research, University of Navarra, 31008 Navarra, Spain.
authors.forename: Maria
authors.initials: M
authors.lastname: Castle
authors.forename: Maria S
authors.initials: MS
authors.lastname: Aymerich
authors.forename: Carlos
authors.initials: C
authors.lastname: Sanchez-Escobar
authors.forename: Nancy
authors.initials: N
authors.lastname: Gonzalo
authors.forename: José A
authors.initials: JA
authors.lastname: Obeso
authors.forename: José L
authors.initials: JL
authors.lastname: Lanciego
mesh_terms: D000818:Animals; D001369:Axons / Q000502:physiology / Q000648:ultrastructure*; D001479:Basal Ganglia / Q000166:cytology* / Q000502:physiology; D001710:Biotin / Q000031:analogs & derivatives*; D002772:Cholera Toxin; D003911:Dextrans; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D005917:Globus Pallidus / Q000166:cytology / Q000502:physiology; D020646:Intralaminar Thalamic Nuclei / Q000166:cytology* / Q000502:physiology; D017072:Neostriatum / Q000166:cytology / Q000502:physiology; D009434:Neural Pathways / Q000166:cytology* / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D013266:Stilbamidines; D013378:Substantia Nigra / Q000166:cytology / Q000502:physiology; D020531:Subthalamic Nucleus / Q000166:cytology / Q000502:physiology
chemical_list: C049774:2-hydroxy-4,4'-diamidinostilbene, methanesulfonate salt; D003911:Dextrans; D013266:Stilbamidines; C076397:biotinylated dextran amine; D001710:Biotin; D002772:Cholera Toxin