title: Structural development and dorsoventral maturation of the medial entorhinal cortex.
abstract: We investigated the structural development of superficial-layers of medial entorhinal cortex and parasubiculum in rats. The grid-layout and cholinergic-innervation of calbindin-positive pyramidal-cells in layer-2 emerged around birth while reelin-positive stellate-cells were scattered throughout development. Layer-3 and parasubiculum neurons had a transient calbindin-expression, which declined with age. Early postnatally, layer-2 pyramidal but not stellate-cells co-localized with doublecortin - a marker of immature neurons - suggesting delayed functional-maturation of pyramidal-cells. Three observations indicated a dorsal-to-ventral maturation of entorhinal cortex and parasubiculum: (i) calbindin-expression in layer-3 neurons decreased progressively from dorsal-to-ventral, (ii) doublecortin in layer-2 calbindin-positive-patches disappeared dorsally before ventrally, and (iii) wolframin-expression emerged earlier in dorsal than ventral parasubiculum. The early appearance of calbindin-pyramidal-grid-organization in layer-2 suggests that this pattern is instructed by genetic information rather than experience. Superficial-layer-microcircuits mature earlier in dorsal entorhinal cortex, where small spatial-scales are represented. Maturation of ventral-entorhinal-microcircuits - representing larger spatial-scales - follows later around the onset of exploratory behavior.
authors.affiliation: Bernstein Center for Computational Neuroscience, Humboldt University of Berlin, Berlin, Germany.
authors.forename: Saikat
authors.identifier: http://orcid.org/0000-0002-2732-6612
authors.initials: S
authors.lastname: Ray
authors.affiliation: Bernstein Center for Computational Neuroscience, Humboldt University of Berlin, Berlin, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Brecht
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000032:analysis; D064026:Calbindins / Q000032:analysis; D002148:Calmodulin-Binding Proteins / Q000032:analysis; D002454:Cell Differentiation; D000089622:Doublecortin Domain Proteins; D000089662:Doublecortin Protein; D018728:Entorhinal Cortex / Q000196:embryology*; D015870:Gene Expression; D008565:Membrane Proteins / Q000032:analysis; D008869:Microtubule-Associated Proteins / Q000032:analysis; D009474:Neurons / Q000737:chemistry / Q000502:physiology*; D009479:Neuropeptides / Q000032:analysis; D051381:Rats; D000091042:Reelin Protein
chemical_list: D015415:Biomarkers; D064026:Calbindins; D002148:Calmodulin-Binding Proteins; C000714848:Dcx protein, rat; D000089622:Doublecortin Domain Proteins; D000089662:Doublecortin Protein; D008565:Membrane Proteins; D008869:Microtubule-Associated Proteins; D009479:Neuropeptides; D000091042:Reelin Protein; C000717129:Reln protein, rat; C541096:WFS1 protein, rat
keywords: calbindin patches; doublecortin; immature neurons; medial entorhinal cortex; neuroscience; parasubiculum; pyramidal neurons; rat