The brain of the tree pangolin ( Manis tricuspis ). II. The olfactory system

et al. 2019

Self Cite

Employing a range of standard and immunohistochemical stains we provide a description of the hippocampal formation in the brain of the tree pangolin. For the most part, the architecture, chemical neuroanatomy, and topological relationships of the component parts of the hippocampal formation of the tree pangolin were consistent with that observed in other mammalian species. Within the hippocampus proper fields CA1, 3, and 4 could be identified with certainty, while CA2 was tentatively identified as a small transitional zone between the CA1 and CA3 fields. Within the dentate gyrus evidence for adult hippocampal neurogenesis at a rate comparable to other mammals was observed. The subicular complex and entorhinal cortex also exhibited divisions typically observed in other mammalian species. In contrast to many other mammals, an architecturally and neurochemically distinct CA4 field was observed, supporting Lorente de Nó's proposed CA4 field, at least in some mammalian species. In addition, up to seven laminae were evident in the dentate gyrus. Calretinin immunostaining revealed the three sublamina of the molecular layer, while immunostaining for vesicular glutamate transporter 2 and neurofilament H indicate that the granule cell layer was composed of two sublamina. The similarities and differences observed in the tree pangolin indicate that the hippocampal formation is an anatomically and neurochemically conserved neural unit in mammalian evolution, but minor changes may relate to specific life history features and habits of species.

Section: Resultssupporting

confidence: 71%

The brain of the tree pangolin (Manis tricuspis). IV. The hippocampal formation

et al. 2019

Self Cite

“…The sounds created by ants are generally through the process of stridulation, and there are variations in these sounds based on the numbers of ants present and the activity of the ants (Hickling & Brown, ). Thus, it might be speculated that in addition to olfaction as a method of locating nutrition (Imam, Bhagwandin, Ajao, Spocter, et al, ), the pangolins may localize large ant or termite populations using audition, with the potentially specialized isofrequency modules of the MGv playing a role in guiding the pangolins to the most abundant source. These speculations may be tested behaviorally and may reveal unknown pangolin behaviors, enhancing our understanding of their biology and life history.…”

Section: Discussionmentioning

confidence: 99%

“…Here, we continue our systematic analysis of the brain of the tree pangolin (Imam, Ajao, Bhagwandin, Ihunwo, & Manger, 2017;Imam, Bhagwandin, Ajao, Spocter, et al, 2018;Imam, Bhagwandin, Ajao, Ihunwo, Fuxe, et al, 2018; by providing a detailed account of the architecture of the tree pangolin diencephalon and hypothalamus using Nissl and myelin staining in conjunction with a range of immunohistochemical stains.…”

Section: Introductionmentioning

confidence: 96%

The brain of the tree pangolin (Manis tricuspis). V. The diencephalon and hypothalamus

et al. 2019

Self Cite

The diencephalon (dorsal thalamus, ventral thalamus, and epithalamus) and the hypothalamus, play central roles in the processing of the majority of neural information within the central nervous system. Given the interactions of the diencephalon and hypothalamus with virtually all portions of the central nervous system, the comparative analysis of these regions lend key insights into potential neural, evolutionary, and behavioral specializations in different species. Here, we continue our analysis of the brain of the tree pangolin by providing a comprehensive description of the organization of the diencephalon and hypothalamus using a range of standard and immunohistochemical staining methods. In general, the diencephalon and hypothalamus of the tree pangolin follow the organization typically observed across mammals. No unusual structural configurations of the ventral thalamus, epithalamus, or hypothalamus were noted. Within the dorsal thalamus, the vast majority of typically identified nuclear groups and component nuclei were observed. The visual portion of the tree pangolin dorsal thalamus appears to be organized in a manner not dissimilar to that seen in most nonprimate and noncarnivore mammals, and lacks certain features that are present in the closely related carnivores. Within the ventral medial geniculate nucleus, a modular organization, revealed with parvalbumin neuropil immunostaining, is suggestive of specialized auditory processing in the tree pangolin. In addition, a potential absence of hypothalamic cholinergic neurons is suggestive of unusual patterns of sleep. These observations are discussed in an evolutionary and functional framework regarding the phylogeny and life history of the pangolins.

“…The right half of the brain of MT5 was sectioned in the sagittal plane and a 1 in 10 series of sections taken and stained for Nissl, myelin, TH, 5HT, PV, CB, CR, SMI‐32, vGlut2, and doublecortin (DCX). Complete details of staining for Nissl and myelin staining, and also for antibody characterization, specificity, and the protocol followed for all immunostains listed above, have been provided previously (Imam, Bhagwandin, Ajao, Spocter, Ihunwo, & Manger, ).…”

Section: Methodsmentioning

confidence: 99%

“…Here we expand our systematic analysis of the brain of the tree pangolin (Imam, Ajao, Bhagwandin, Ihunwo, & Manger, ; Imam et al, ; Imam et al, ; Imam, Bhagwandin, Ajao, Ihunwo, & Manger, ; Imam, Bhagwandin, Ajao, & Manger, ) by providing a detailed account of the architecture of the tree pangolin brainstem and cerebellum (diencephalic prosomere 1 through to rhombomere 11) using Nissl and myelin staining in conjunction with a range of immunohistochemical stains.…”

Section: Introductionmentioning

confidence: 99%

The brain of the tree pangolin (Manis tricuspis). VI. The brainstem and cerebellum

et al. 2019

Self Cite

The brainstem (midbrain, pons, and medulla oblongata) and cerebellum (diencephalic prosomere 1 through to rhombomere 11) play central roles in the processing of sensorimotor information, autonomic activity, levels of awareness and the control of functions external to the conscious cognitive world of mammals. As such, comparative analyses of these structures, especially the understanding of specializations or reductions of structures with functions that have been elucidated in commonly studied mammalian species, can provide crucial information for our understanding of the behavior of less commonly studied species, like pangolins. In the broadest sense, the nuclear complexes and subdivisions of nuclear complexes, the topographical arrangement, the neuronal chemistry, and fiber pathways of the tree pangolin conform to that typically observed across more commonly studied mammalian species. Despite this, variations in regions associated with the locus coeruleus complex, auditory system, and motor, neuromodulatory and autonomic systems involved in feeding, were observed in the current study. While we have previously detailed the unusual locus coeruleus complex of the tree pangolin, the superior olivary nuclear complex of the auditory system, while not exhibiting additional nuclei or having an altered organization, this nuclear complex, particularly the lateral superior olivary nucleus and nucleus of the trapezoid body, shows architectonic refinement. The cephalic decussation of the pyramidal tract, an enlarged hypoglossal nucleus, an additional subdivision of the serotonergic raphe obscurus nucleus, and the expansion of the superior salivatory nucleus, all indicate neuronal specializations related to the myrmecophagous diet of the pangolins.