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Published in Terence R. Anthoney, Neuroanatomy and the Neurologic Exam, 2017
One could argue that the ependyma is really a ventricular lining, external to the hippocampus itself, and, likewise, that the alveus is a layer of efferent fibers rather than part of the hippocampal cortex. Presumably for similar reasons, Martinez Martinez excludes the ependyma, describing only the remaining six “layers” (1982, p. 259–260); and Carpenter and Sutin exclude the ependyma and the alveus, describing only the remaining five “laminae” in the hippocampal cortex (1983, p. 626).
ENTRIES A–Z
Published in Philip Winn, Dictionary of Biological Psychology, 2003
The fimbria is a thin band of WHITE MATTER situated laterally in the HIPPOCAMPAL FORMATION. It consists of axons from the PYRAMIDAL NEURONS of the HIPPOCAMPUS and SUBICULUM as well as AFFERENT or incoming fibres to the hippocampal formation. The pyramidal axons initially form the ALVEUS which spreads over the ventricular surface of the hippocampus. The alveus gradually thickens towards the dorsal end of the hippocampus to form the fimbria. The fimbriae from the two sides then merge to form the FORNIX, which projects to the septal region (see SEPTAL NUCLEI) and the HYPOTHALAMUS.
The effect of experimentally-induced diabetes on rat hippocampus and the potential neuroprotective effect of Cerebrolysin combined with insulin. A histological and immunohistochemical study
Published in Egyptian Journal of Basic and Applied Sciences, 2023
Doaa El-Adli, Salwa A. Gawish, Amany AbdElFattah Mohamed AbdElFattah, Mona Fm. Soliman
The hippocampal formation consisted of hippocampus proprius, dentate gyrus (DG) and the subicular cortex (SC). The hippocampus proprius could be differentiated into CA1, CA2, CA3 and CA4 regions. The DG had a crest and upper and lower blades surrounding CA4 (Figure 1 (a and b)). The hippocampus proprius was formed of the following layers; the alveus, stratum oriens (st.or), stratum pyramidale (st.py), stratum radiatum (st.rd) and stratum lacunosum-moleculare (st.lm). The alveus was the innermost layer containing nerve fibers and neuroglial cells. St.or showed scattered cells within the nerve fibers. St.py consisted of 5–6 layers of pyramidal cells. St.rd showed a radial streaking pattern of fibers. Finally, St.lm showed horizontal fibers, neuroglial cells and blood vessels (Figure 1 (c)). Pyramidal cells of CA3 appeared as large sized, loosely packed triangular cells with vesicular nuclei and prominent nucleoli. Each cell showed an apical dendrite ramifying toward St.rd and basal dendrites (Figure 1 (d)). The DG consisted of molecular, granular and polymorphic layers. The polymorphic layer showed scattered polymorphic nuclei. The granule cell layer (GCL) contained 8–9 compactly arranged layers of granule cells with vesicular nuclei and prominent nucleoli. Spindle-shaped immature cells with oval darkly stained nuclei were seen in the subgranular zone (SGZ) (Figure 1 (e and f)).
Morphological study of the postnatal hippocampal development in the TRPV1 knockout mice
Published in Temperature, 2023
Melinda Boros, Noémi Sóki, Abigél Molnár, Hajnalka Ábrahám
At the age of P5, only a few MBP- immunoreactive oligodendroglial cells could be detected in the fimbria fornicis (Figure 9a-b). The numbers of MBP-positive oligodendroglial cells increased, and the first myelinated thin axons could observed in the fimbria fornicis by P7 both in KO and control mice (Figure 9c-d). At the age of P10, myelinated axons were present in the fimbria fornicis as well as in the alveus of the Ammon’s horn of both strains (Figure 9e-f). By P14, myelinated axons were present in the stratum lacunosum-moleculare of CA1, as well as in stratum radiatum of CA3 (Figure 10a-b), and few myelinated axons were visible in the molecular layer of the dentate gyrus in TRPV1 KO as well as in controls. Later, at P21 and P28, myelinated axons appeared in the stratum oriens and in the hilus of the dentate gyrus in both strains (Figure 10c-f).
Tramadol administration induced hippocampal cells apoptosis, astrogliosis, and microgliosis in juvenile and adult male mice, histological and immunohistochemical study
Published in Ultrastructural Pathology, 2020
Ola A. Hussein, Asmaa Fathi Abdel Mola, Amal Rateb
As regards to the CA1 field of control AH, H& E stained sections revealed the following strata in order, from the alveus to the hippocampal fissure, stratum oriens, stratum pyramidal, and stratum radiatum. The pyramidal neurons were the principal cell type in the CA1 field and their triangular perikarya were closely located in stratum pyramidal. These neurons were medium-sized and smaller than those of the CA3 field. They contained rounded vesicular nuclei and basophilic cytoplasm. Scattered cells and blood capillaries were also noticed (Figure 3a). CA1 field of adult tramadol-treated group showed few dark shrunken pyramidal neurons, whereas, the majority of cells showed the normal appearance (Figure 3b). Empty areas were seen around blood capillaries. In the tramadol juvenile treated group, CA1 revealed many dark shrunken pyramidal neurons surrounded by empty spaces and wide spaces were observed around blood capillaries (Figure 3c).