Journal: Brain structure & function
Article Title: Sub-circuit alterations in dorsal hippocampus structure, and function after global neurodevelopmental insult
doi: 10.1007/s00429-018-1704-3
Figure Lengend Snippet: A) Golgi impregnated tissue was used to examine layer thicknesses, primary cell morphology, and spines. It can be seen from the tissue and the reconstructed neurons that the CA1 pyramidal layer is compressed in GD17-MAM rats. B) The hippocampus circuit receives its main input from the entorhinal cortex at both the molecular layer of DG (EC II) and in slm of CA1 (EC III). Information is transferred from DG to CA3 and then from CA3 to str. rad. of CA1. CA1 then acts as the main output of the hippocampus circuit. C) The stratum oriens, pyramidal and str. rad. of CA1 are significantly thinned in GD17-MAM rats compared to control rats (so: Group: t6 = 3.52; p = 0.01; pyr: t6 = 2.86; p = 0.03; str. rad.: t6 = 6.78; p < 0.001; slm: t6 = 1.75; p = 0.13; mol: t6 = 0.53; p = 0.61; grc: t6 = 1.40; p = 0.21. Control, n = 4; GD17-MAM, n = 4). D) Example Neurolucida reconstructions of granule cells from control and GD17-MAM rats (left panel) show similar cell morphologies. Dendritic length increases with distance from the cell body similarly in GD17-MAM and control rats (middle panel) and is not different between GD17-MAM and control rats in any sublayer of the molecular layer (right panel, inner mol: t30 = 0.70, p = 0.49; middle mol: t30 = 0.61, p = 0.55; outer mol: t30 = 0.23, p = 0.81). E) Branch order is also not different between GD17-MAM and control rats (1–3 branch order: t30 = 0.85, p = 0.40. ≥ 4 branch order: t30 = 0.28, p = 0.78. Granule cell neurons: Control, n = 16. GD17-MAM, n = 16). Spines were classified as thin, filipodia, mushroom, and stubby. In spite of similar overall morphology, GD17-MAM rats have an increased number of total spines per μm of branch length (thin: t46 = 1.25, p = 0.21; filipodia: t46 = 1.63, p = 0.11; mushroom: t46 = 0.75, p = 0.46; stubby: t46 = 1.13, p = 0.27; total: t46 = 2.39, p = 0.02. Branch segments: Control, n = 24; GD17-MAM, n = 24). F) Example Neurolucida reconstructions of CA1 pyramidal cells from control and GD17-MAM rats (left panel). Dendritic length of pyramidal neurons extends farther from the cell body in control rats (middle panel), and the total length within the str. rad. of CA1 is reduced in GD17-MAM rats while total branching in slm is not different (right panel, str. rad.: t23 = 2.30, p = 0.03. slm: t23 = 1.41, p = 0.17). Pyramidal neurons: Control, n = 14; GD17-MAM, n = 11. For D and F: Data is mean ± SEM for any concentric circle (distance from the neuron) that had more than 8 neurons. For all other graphs, data is mean ± SEM.
Article Snippet: Three measurements were taken for each layer ( stratum oriens , stratum pyramidale , stratum radiatum (str. rad.), stratum lacunosum moleculare (slm) , molecular layer, and granule cell layer) using the quick measure tool of Neurolucida morphometry software (version 11.11.2, Microbrightfield, Inc., Cholchester, VT) at 4× magnification using an Olympus BX5T microscope.
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