Hippocampal pyramidal cells: the reemergence of cortical lamination.
Bottom Line: Distributions of deep and superficial pyramidal cell dendrites and studies in reeler or sparsely GFP-expressing mice indicate that this also applies to afferent pathways.Histological, neurochemical, and connective differences between deep and superficial neurons may correlate with (patho-) physiological phenomena specific to pyramidal cells at different radial locations.We feel that an appreciation of radial subdivisions in the pyramidal cell layer reminiscent of lamination in other cortical areas may be critical in the interpretation of studies of hippocampal anatomy and function.
Affiliation: Institute of Anatomy, University of Zürich, 8057 Zürich, Switzerland. email@example.comShow MeSH
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Mentions: We follow Ishizuka et al. (1990) and use the terms proximal (nearer the dentate gyrus) and distal (further away from the dentate gyrus) to designate positions along the transverse axis of the CA1 and CA3. The terms septal (closer, by way of the fimbria, to the septum) and temporal (further away from the septum) are used to designate positions along the longitudinal axis of the hippocampus. This nomenclature is independent of differences in position that accompany phylogenetic changes in the size and shape of the adjacent cortical areas. Molecular and connectional criteria have replaced the original definition of CA2 based on Golgi stains (Lein et al. 2005). With one exception (see Neurochemistry), we did not find evidence that would distinguish this field from CA1 as far as lamination is concerned, and it is here treated as the part of CA1. For the sake of simplicity, we use “CA1” throughout instead of the more correct “CA1/2”. Terms and definitions are illustrated in Fig. 1.Fig. 1
Affiliation: Institute of Anatomy, University of Zürich, 8057 Zürich, Switzerland. firstname.lastname@example.org