Heterogeneity of spine density in pyramidal neurons of isocortex of mongoose, Herpestes edwardsii (É. Geoffroy Saint‐Hilaire 1818)

Abstract

The characteristics of pyramidal neurons within six layers of Indian gray mongoose (Herpestes edwardsii) isocortex have been investigated using Golgi and Cresyl-Violet methods. Pyramidal neurons and the cytoarchitecture of isocortex of mongoose were photographed with the help of computer aided Nikon eclipse 80i microscope whereas the lucida drawings were made by simple light microscope equipped with camera lucida. The cortical neurons exhibit marked regional differences in phenotype. The differences occur in morphology and distribution of spines within the cortical neurons not only among different species but also within an animal's brain. The present investigation aims at studying the features of pyramidal neurons and to find out the differences if any in distribution of spines in different layers (II-VI) as well as regions (Frontal, Temporal, Parietal, and Occipital) of isocortex of mongoose, which will provide information regarding importance of different layer and region. This piece of work embarks the findings that spine density shows inter-regional as well as interlaminar variations within isocortex of mongoose indicating that pyramidal cells present in varied layer and region are not equally functional and there do exists differences in activity among layers and regions. Among regions, the Temporal region possessing highest spine density contributes more toward functioning of mongoose isocortex and might play significant role in predatory nature of mongoose because this region in mammals is associated with auditory, visual perception, and object recognition.

Comparative morphology of gigantopyramidal neurons in primary motor cortex across mammals

“…The current results supplement a growing comparative database of neuronal morphology (Ascoli, Donohue, & Halavi, 2007;Bianchi et al, 2013;Butti et al, 2015;Jacobs et al, 2011Jacobs et al, , 2014Jacobs, Harland, et al, 2015;Johnson et al, 2016;Reyes, Harland, Reep, Sherwood, & Jacobs, 2016) generally consistent with what has been observed previously in placental mammals (carnivores: Fox, Inman, & Himwich, 1966;H€ ubener, Schwarz, & Bolz, 1990;Matsubara, Chase, & Thejomayen, 1996;Srivastava, Singh, & Chauhan, 2013;Winer, 1984;Yamamoto, Samejima, & Oka, 1987;cetartiodactyls: Butti et al, 2014cetartiodactyls: Butti et al, , 2015primates: Bianchi et al, 2013;de Lima, Voigt, & Morrison, 1990;Elston, Benavides-Piccione, & DeFelipe, 2001;Feldman, 1984;Meyer, 1987;Mohan et al, 2015;Valverde, 1986). Statistically, the specific constellation of somatodendritic measures for superficial and gigantopyramidal neurons could be used to accurately distinguish taxonomic groups.…”

“…The present study constitutes the first comparative exploration of quantitative dendritic morphology in gigantopyramidal neurons. The morphological findings in superficial and deep pyramidal neurons are generally consistent with what has been observed previously in placental mammals (carnivores: Fox, Inman, & Himwich, ; Hübener, Schwarz, & Bolz, ; Matsubara, Chase, & Thejomayen, ; Srivastava, Singh, & Chauhan, ; Winer, ; Yamamoto, Samejima, & Oka, ; cetartiodactyls: Butti et al, ; primates: Bianchi et al, ; de Lima, Voigt, & Morrison, ; Elston, Benavides‐Piccione, & DeFelipe, ; Feldman, ; Ghosh & Porter, ; Meyer, ; Mohan et al, ; Valverde, ). Statistically, the specific constellation of somatodendritic measures for superficial and gigantopyramidal neurons could be used to accurately distinguish taxonomic groups.…”