title: Identification of the anterior nucleus of the ansa lenticularis in birds as the homolog of the mammalian subthalamic nucleus.
abstract: In mammals, the subthalamic nucleus (STN) is a glutamatergic diencephalic cell group that develops in the caudal hypothalamus and migrates to a position above the cerebral peduncle. By its input from the external pallidal segment and projection to the internal pallidal segment, STN plays a critical role in basal ganglia functions. Although the basal ganglia in birds is well developed, possesses the same major neuron types as in mammals, and plays a role in movement control similar to that in mammals, it has been uncertain whether birds possess an STN. We report here evidence indicating that the so-called anterior nucleus of the ansa lenticularis (ALa) is the avian homolog of mammalian STN. First, the avian ALa too develops within the mammillary hypothalamic area and migrates to a position adjacent to the cerebral peduncle. Second, ALa specifically receives input from dorsal pallidal neurons that receive input from enkephalinergic striatal neurons, as is true of STN. Third, ALa projects back to avian dorsal pallidum, as also the case for STN in mammals. Fourth, the neurons of ALa contain glutamate, and the target neurons of ALa in dorsal pallidum possess AMPA-type glutamate receptor profiles resembling those of mammalian pallidal neurons. Fifth, unilateral lesions of ALa yield behavioral disturbances and movement asymmetries resembling those observed in mammals after STN lesions. These various findings indicate that ALa is the avian STN, and they suggest that the output circuitry of the basal ganglia for motor control is similar in birds and mammals.
authors.affiliation: Department of Anatomy and Neurobiology, University of Tennessee-Memphis, Memphis, Tennessee 38163, USA.
authors.forename: Y
authors.initials: Y
authors.lastname: Jiao
authors.forename: L
authors.initials: L
authors.lastname: Medina
authors.forename: C L
authors.initials: CL
authors.lastname: Veenman
authors.forename: C
authors.initials: C
authors.lastname: Toledo
authors.forename: L
authors.initials: L
authors.lastname: Puelles
authors.forename: A
authors.initials: A
authors.lastname: Reiner
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D005075:Biological Evolution; D001717:Birds / Q000033:anatomy & histology* / Q000196:embryology; D002642:Chick Embryo; D002645:Chickens; D010856:Columbidae; D018491:Dopamine Agonists / Q000494:pharmacology; D005917:Globus Pallidus / Q000378:metabolism; D018698:Glutamic Acid / Q000378:metabolism; D007608:Kainic Acid / Q000008:administration & dosage; D008322:Mammals / Q000033:anatomy & histology* / Q000196:embryology; D008845:Microinjections; D009415:Nerve Net; D009434:Neural Pathways / Q000033:anatomy & histology* / Q000502:physiology; D009474:Neurons / Q000166:cytology; D051381:Rats; D018091:Receptors, AMPA / Q000378:metabolism; D017470:Receptors, Glutamate / Q000378:metabolism; D013045:Species Specificity; D020531:Subthalamic Nucleus / Q000033:anatomy & histology* / Q000196:embryology; D020530:Subthalamus / Q000033:anatomy & histology* / Q000187:drug effects / Q000196:embryology / Q000378:metabolism
chemical_list: D018491:Dopamine Agonists; D018091:Receptors, AMPA; D017470:Receptors, Glutamate; D018698:Glutamic Acid; D007608:Kainic Acid