title: Two functionally distinct networks of gap junction-coupled inhibitory neurons in the thalamic reticular nucleus.
abstract: Gap junctions (GJs) electrically couple GABAergic neurons of the forebrain. The spatial organization of neuron clusters coupled by GJs is an important determinant of network function, yet it is poorly described for nearly all mammalian brain regions. Here we used a novel dye-coupling technique to show that GABAergic neurons in the thalamic reticular nucleus (TRN) of mice and rats form two types of GJ-coupled clusters with distinctive patterns and axonal projections. Most clusters are elongated narrowly along functional modules within the plane of the TRN, with axons that selectively inhibit local groups of relay neurons. However, some coupled clusters have neurons arrayed across the thickness of the TRN and target their axons to both first- and higher-order relay nuclei. Dye coupling was reduced, but not abolished, among cells of connexin36 knock-out mice. Our results suggest that GJs form two distinct types of inhibitory networks that correlate activity either within or across functional modules of the thalamus.
authors.affiliation: Department of Neuroscience, Division of Biology and Medicine, Brown University, Providence, Rhode Island 02912 seungchannlee@gmail.com bc@brown.edu.
authors.forename: Seung-Chan
authors.initials: SC
authors.lastname: Lee
authors.affiliation: Department of Neuroscience, Division of Biology and Medicine, Brown University, Providence, Rhode Island 02912.
authors.forename: Saundra L
authors.initials: SL
authors.lastname: Patrick
authors.affiliation: Department of Neuroscience, Division of Biology and Medicine, Brown University, Providence, Rhode Island 02912.
authors.forename: Kristen A
authors.initials: KA
authors.lastname: Richardson
authors.affiliation: Department of Neuroscience, Division of Biology and Medicine, Brown University, Providence, Rhode Island 02912 seungchannlee@gmail.com bc@brown.edu.
authors.forename: Barry W
authors.initials: BW
authors.lastname: Connors
mesh_terms: D000818:Animals; D001369:Axons / Q000378:metabolism / Q000502:physiology; D017630:Connexins / Q000235:genetics / Q000378:metabolism; D054351:Electrical Synapses / Q000378:metabolism / Q000502:physiology*; D059330:GABAergic Neurons / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D007395:Interneurons / Q000166:cytology / Q000378:metabolism / Q000502:physiology; D020646:Intralaminar Thalamic Nuclei / Q000166:cytology* / Q000502:physiology; D051379:Mice; D008810:Mice, Inbred C57BL; D009433:Neural Inhibition; D051381:Rats; D017207:Rats, Sprague-Dawley; D000097004:Gap Junction delta-2 Protein
chemical_list: D017630:Connexins; D000097004:Gap Junction delta-2 Protein
keywords: dye-coupling; electrical coupling; electrical synapses; gap junctions; thalamic reticular nucleus