title: Toward a self-wired active reconstruction of the hippocampal trisynaptic loop: DG-CA3.
abstract: The mammalian hippocampus functions to encode and retrieve memories by transiently changing synaptic strengths, yet encoding in individual subregions for transmission between regions remains poorly understood. Toward the goal of better understanding the coding in the trisynaptic pathway from the dentate gyrus (DG) to the CA3 and CA1, we report a novel microfabricated device that divides a micro-electrode array into two compartments of separate hippocampal network subregions connected by axons that grow through 3 × 10 × 400 μm tunnels. Gene expression by qPCR demonstrated selective enrichment of separate DG, CA3, and CA1 subregions. Reconnection of DG to CA3 altered burst dynamics associated with marked enrichment of GAD67 in DG and GFAP in CA3. Surprisingly, DG axon spike propagation was preferentially unidirectional to the CA3 region at 0.5 m/s with little reverse transmission. Therefore, select hippocampal subregions intrinsically self-wire in anatomically appropriate patterns and maintain their distinct subregion phenotype without external inputs.
authors.affiliation: Department of Medical Microbiology, Immunology and Cell Biology, Southern Illinois University School of Medicine Springfield, IL, USA ; Department of Neurology, Southern Illinois University School of Medicine Springfield, IL, USA.
authors.forename: Gregory J
authors.initials: GJ
authors.lastname: Brewer
authors.forename: Michael D
authors.initials: MD
authors.lastname: Boehler
authors.forename: Stathis
authors.initials: S
authors.lastname: Leondopulos
authors.forename: Liangbin
authors.initials: L
authors.lastname: Pan
authors.forename: Sankaraleengam
authors.initials: S
authors.lastname: Alagapan
authors.forename: Thomas B
authors.initials: TB
authors.lastname: DeMarse
authors.forename: Bruce C
authors.initials: BC
authors.lastname: Wheeler
mesh_terms: D000818:Animals; D056654:CA3 Region, Hippocampal / Q000502:physiology*; D018891:Dentate Gyrus / Q000502:physiology*; D006624:Hippocampus / Q000502:physiology*; D008959:Models, Neurological; D009434:Neural Pathways / Q000502:physiology; D009474:Neurons / Q000502:physiology*; D051381:Rats; D013569:Synapses / Q000502:physiology*
keywords: GAD67; GFAP; burst; dentate gyrus; multielectrode array