title: Cell-type-specific circuit connectivity of hippocampal CA1 revealed through Cre-dependent rabies tracing.
abstract: We developed and applied a Cre-dependent, genetically modified rabies-based tracing system to map direct synaptic connections to specific CA1 neuron types in the mouse hippocampus. We found common inputs to excitatory and inhibitory CA1 neurons from CA3, CA2, the entorhinal cortex (EC), the medial septum (MS), and, unexpectedly, the subiculum. Excitatory CA1 neurons receive inputs from both cholinergic and GABAergic MS neurons, whereas inhibitory neurons receive a great majority of inputs from GABAergic MS neurons. Both cell types also receive weaker input from glutamatergic MS neurons. Comparisons of inputs to CA1 PV+ interneurons versus SOM+ interneurons showed similar strengths of input from the subiculum, but PV+ interneurons received much stronger input than SOM+ neurons from CA3, the EC, and the MS. Thus, rabies tracing identifies hippocampal circuit connections and maps how the different input sources to CA1 are distributed with different strengths on each of its constituent cell types.
authors.affiliation: Department of Anatomy and Neurobiology, School of Medicine, University of California, Irvine, Irvine, CA 92697-1275, USA.
authors.forename: Yanjun
authors.initials: Y
authors.lastname: Sun
authors.affiliation: Department of Anatomy and Neurobiology, School of Medicine, University of California, Irvine, Irvine, CA 92697-1275, USA.
authors.forename: Amanda Q
authors.initials: AQ
authors.lastname: Nguyen
authors.affiliation: Department of Anatomy and Neurobiology, School of Medicine, University of California, Irvine, Irvine, CA 92697-1275, USA.
authors.forename: Joseph P
authors.initials: JP
authors.lastname: Nguyen
authors.affiliation: Department of Anatomy and Neurobiology, School of Medicine, University of California, Irvine, Irvine, CA 92697-1275, USA.
authors.forename: Luc
authors.initials: L
authors.lastname: Le
authors.affiliation: II. Medizinische Klinik, Klinikum rechts der Isar, Technische Universität München, 81675 Munich, Germany.
authors.forename: Dieter
authors.initials: D
authors.lastname: Saur
authors.affiliation: Systems Neurobiology Laboratories, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA.
authors.forename: Jiwon
authors.initials: J
authors.lastname: Choi
authors.affiliation: Systems Neurobiology Laboratories, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA.
authors.forename: Edward M
authors.initials: EM
authors.lastname: Callaway
authors.affiliation: Department of Anatomy and Neurobiology, School of Medicine, University of California, Irvine, Irvine, CA 92697-1275, USA; Department of Biomedical Engineering, University of California, Irvine, Irvine, CA 92697-2715, USA; Department of Microbiology and Molecular Genetics, School of Medicine, University of California, Irvine, Irvine, CA 92697-4025, USA. Electronic address: xiangmin.xu@uci.edu.
authors.forename: Xiangmin
authors.initials: X
authors.lastname: Xu
mesh_terms: D000818:Animals; D056547:CA1 Region, Hippocampal / Q000473:pathology*; D007395:Interneurons / Q000473:pathology*; D051379:Mice; D008822:Mice, Transgenic; D009434:Neural Pathways / Q000502:physiology; D009474:Neurons / Q000473:pathology; D011818:Rabies / Q000473:pathology*; D011820:Rabies virus / Q000145:classification*