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Mossy Cells in the Dorsal and Ventral Dentate Gyrus Differ in Their Patterns of Axonal Projections.
Houser, Carolyn R; Peng, Zechun; Wei, Xiaofei; Huang, Christine S; Mody, Istvan.
Afiliación
  • Houser CR; Department of Neurobiology houser@mednet.ucla.edu.
  • Peng Z; Brain Research Institute, David Geffen School of Medicine at the University of California, Los Angeles, Los Angeles, California 90095.
  • Wei X; Department of Neurobiology.
  • Huang CS; Department of Neurology.
  • Mody I; Department of Neurobiology.
J Neurosci ; 41(5): 991-1004, 2021 02 03.
Article en En | MEDLINE | ID: mdl-33268544
Mossy cells (MCs) of the dentate gyrus (DG) are a major group of excitatory hilar neurons that are important for regulating activity of dentate granule cells. MCs are particularly intriguing because of their extensive longitudinal connections within the DG. It has generally been assumed that MCs in the dorsal and ventral DG have similar patterns of termination in the inner one-third of the dentate molecular layer. Here, we demonstrate that axonal projections of MCs in these two regions are considerably different. MCs in dorsal and ventral regions were labeled selectively with Cre-dependent eYFP or mCherry, using two transgenic mouse lines (including both sexes) that express Cre-recombinase in MCs. At four to six weeks following unilateral labeling of MCs in the ventral DG, a dense band of fibers was present in the inner one-fourth of the molecular layer and extended bilaterally throughout the rostral-caudal extent of the DG, replicating the expected distribution of MC axons. In contrast, following labeling of MCs in the dorsal DG, the projections were more diffusely distributed. At the level of transfection, fibers were present in the inner molecular layer, but they progressively expanded into the middle molecular layer and, most ventrally, formed a distinct band in this region. Optical stimulation of these caudal fibers expressing ChR2 demonstrated robust EPSCs in ipsilateral granule cells and enhanced the effects of perforant path stimulation in the ventral DG. These findings suggest that MCs in the dorsal and ventral DG differ in the distribution of their axonal projections and possibly their function.SIGNIFICANCE STATEMENT Mossy cells (MCs), a major cell type in the hilus of the dentate gyrus (DG), are unique in providing extensive longitudinal and commissural projections throughout the DG. Although it has been assumed that all MCs have similar patterns of termination in the inner molecular layer of the DG, we discovered that the axonal projections of dorsal and ventral MCs differ. While ventral MC projections exhibit the classical pattern, with dense innervation in the inner molecular layer, dorsal MCs have a more diffuse distribution and expand into the middle molecular layer where they overlap and interact with innervation from the perforant path. These distinct locations and patterns of axonal projections suggest that dorsal and ventral MCs may have different functional roles.
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Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Axones / Fibras Musgosas del Hipocampo / Potenciales Postsinápticos Excitadores Límite: Animals Idioma: En Revista: J Neurosci Año: 2021 Tipo del documento: Article Pais de publicación: Estados Unidos

Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Axones / Fibras Musgosas del Hipocampo / Potenciales Postsinápticos Excitadores Límite: Animals Idioma: En Revista: J Neurosci Año: 2021 Tipo del documento: Article Pais de publicación: Estados Unidos