The brain of the tree pangolin (Manis tricuspis). VIII. The subpallial telencephalon

Abstract

The current study provides a detailed architectural analysis of the subpallial telencephalon of the tree pangolin. In the tree pangolin, the subpallial telencephalon was divided into septal and striatopallidal regions. The septal region contained the septal nuclear complex, diagonal band of Broca, and the bed nuclei of the stria terminalis. The striatopallidal region comprised of the dorsal (caudate, putamen, internal and external globus pallidus) and ventral (nucleus accumbens, olfactory tubercle, ventral pallidum, nucleus basalis, basal part of the substantia innominata, lateral stripe of the striatum, navicular nucleus, and the major island of Calleja) striatopallidal complexes. In the tree pangolin, the organization and numbers of nuclei forming these regions and complexes, their topographical relationships to each other, and the cyto‐, myelo‐, and chemoarchitecture, were found to be very similar to that observed in commonly studied mammals. Minor variations, such as less nuclear parcellation in the bed nuclei of the stria terminalis, may represent species‐specific variations, or may be the result of the limited range of stains used. Given the overall similarity across mammalian species, it appears that the subpallial telencephalon of the mammalian brain is highly conserved in terms of evolutionary changes detectable with the methods used. It is also likely that the functions associated with these nuclei in other mammals can be translated directly to the tree pangolin, albeit with the understanding that the stimuli that produce activity within these regions may be specific to the life history requirements of the tree pangolin.

The brain of the tree pangolin (Manis tricuspis). IX. The pallial telencephalon

“…Here, we provide a detailed cyto‐, myelo‐, and chemoarchitectonic description of the adult derivatives of the portions of the tree pangolin pallial telencephalon that have not been described previously (e.g., Imam et al., 2017; 2018a; 2019a; 2022a, b). These structures include the claustrum and endopiriform nuclei, the white matter and WMICs, as well as the various areas of the cerebral cortex.…”

“…The current study provides a comprehensive analysis of portions of the pallial telencephalon of the tree pangolin that had not been previously described, including the claustrum and endopiriform nucleus, the subcortical white matter including the WMICs, and the cerebral cortex. Descriptions of the olfactory portions of the pallial telencephalon (Imam et al., 2018a), the hippocampal formation (Imam et al., 2019a), and amygdaloid complex (Imam et al., 2022a, b) have been provided previously and are not considered here. The organization of the pallial telencephalon of the tree pangolin is consistent with that observed across mammals generally, although subtle variations are present.…”

“…The brain of the tree pangolin has been observed to contain all the structures typically forming the mammalian pallial telencephalon (Imam et al., 2017). In addition, detailed descriptions of the olfactory portions of the pallial telencephalon (Imamet al., 2018a), the hippocampal formation (Imam et al., 2019a), and amygdaloid body (Imam et al., 2022a; Imam et al., 2022b) have been provided previously. Here we continue our detailed anatomical description of the structure of the brain of the tree pangolin (Imam et al., 2017; Imam et al., 2018a; Imam et al., 2018b; Imam et al., 2019a; Imam et al., 2019b; Imam et al., 2019c; Imam et al., 2022a, b) by providing a comprehensive architectonic account of the as yet undescribed structures of the pallial telencephalon.…”

“…In addition, detailed descriptions of the olfactory portions of the pallial telencephalon (Imamet al., 2018a), the hippocampal formation (Imam et al., 2019a), and amygdaloid body (Imam et al., 2022a; Imam et al., 2022b) have been provided previously. Here we continue our detailed anatomical description of the structure of the brain of the tree pangolin (Imam et al., 2017; Imam et al., 2018a; Imam et al., 2018b; Imam et al., 2019a; Imam et al., 2019b; Imam et al., 2019c; Imam et al., 2022a, b) by providing a comprehensive architectonic account of the as yet undescribed structures of the pallial telencephalon. The structures include the claustrum and endopiriform nuclear complex (e.g., Real et al., 2003; Smith et al., 2018; Watson & Puelles, 2017), the white matter and white matter interstitial cells (WMICs, e.g., Bhagwandin et al., 2020; Swiegers et al., 2018), and the cerebral cortex (e.g., Homman‐Ludiye et al., 2010; van Essen & Dierker, 2007; van der Gucht et al., 2007).…”

The brain of the tree pangolin (Manis tricuspis). X. The spinal cord

“…Here, we finalize our series describing the anatomy of the central nervous system of the tree pangolin (Imam et al, 2017(Imam et al, , 2018a(Imam et al, , 2018b(Imam et al, , 2019a(Imam et al, , 2019b(Imam et al, , 2019c(Imam et al, , 2022a(Imam et al, , 2022b(Imam et al, , 2022c, by providing a detailed description of the external and internal anatomy of the spinal cord. Due to the foreshortening of the spinal cord of the tree pangolin (Imam et al, 2017), we employ a regional approach in this description, rather than the more commonly used vertebral level approach, as recommended by Sengul et al (2013) for comparative studies.…”