title: Interneurons in the mouse visual thalamus maintain a high degree of retinal convergence throughout postnatal development.
abstract: BACKGROUND
  The dorsal lateral geniculate nucleus (dLGN) of the mouse thalamus has emerged as a powerful experimental system for understanding the refinement of developing sensory connections. Interestingly, many of the basic tenets for such developmental remodeling (for example, pruning of connections to form precise sensory maps) fail to take into account a fundamental aspect of sensory organization, cell-type specific wiring. To date, studies have focused on thalamocortical relay neurons and little is known about the development of retinal connections onto the other principal cell type of dLGN, intrinsic interneurons. Here, we used a transgenic mouse line in which green fluorescent protein (GFP) is expressed within dLGN interneurons (GAD67-GFP), making it possible to visualize them in acutely prepared thalamic slices in order to examine their morphology and functional patterns of connectivity throughout postnatal life.
  
  
  RESULTS
  GFP-expressing interneurons were evenly distributed throughout dLGN and had highly complex and widespread dendritic processes that often crossed eye-specific borders. Estimates of retinal convergence derived from excitatory postsynaptic potential (EPSP) amplitude by stimulus intensity plots revealed that unlike relay cells, interneurons recorded throughout the first 5 weeks of life, maintain a large number (approximately eight to ten) of retinal inputs.
  
  
  CONCLUSIONS
  The lack of pruning onto interneurons suggests that the activity-dependent refinement of retinal connections in dLGN is cell-type specific. The high degree of retinal convergence onto interneurons may be necessary for these cells to provide both widespread and local forms of inhibition in dLGN.
authors.forename: Tania A
authors.initials: TA
authors.lastname: Seabrook
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Krahe
authors.forename: Gubbi
authors.initials: G
authors.lastname: Govindaiah
authors.affiliation: Department of Anatomical Sciences and Neurobiology, University of Louisville, 511 South Floyd Street, Louisville, KY 40202, USA. william.guido@louisville.edu.
authors.forename: William
authors.initials: W
authors.lastname: Guido
mesh_terms: D000818:Animals; D019706:Excitatory Postsynaptic Potentials; D005829:Geniculate Bodies / Q000254:growth & development* / Q000502:physiology; D005968:Glutamate Decarboxylase / Q000378:metabolism; D007395:Interneurons / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D012160:Retina / Q000254:growth & development*; D014795:Visual Pathways / Q000254:growth & development
chemical_list: D005968:Glutamate Decarboxylase; C402565:glutamate decarboxylase 1