Comparative Anatomy and Histology of Elephant, Human, and Tree Shrew Brains

Noppadol Phasukdee; Kewalee  Seeharach; Chaleamchat  Somgird; Taweepoke  Angkavanish; Anucha  Sathanawongs; Sittidet  Mahasawangkul; Chatchote  Thitaram; Ranida  Quiggins

Authors

Noppadol Phasukdee Department of Anatomy, Faculty of Medicine, Chiang Mai University, Thailand https://orcid.org/0000-0001-5855-6149
Kewalee Seeharach Department of Anatomy, Faculty of Medicine, Chiang Mai University, Thailand https://orcid.org/0000-0002-1344-4896
Chaleamchat Somgird Faculty of Veterinary Medicine, Chiang Mai University, Thailand https://orcid.org/0000-0002-4104-526X
Taweepoke Angkavanish The Elephant Reintroduction Foundation, Bangkok, Thailand https://orcid.org/0000-0002-2915-8122
Anucha Sathanawongs Department of Veterinary Bioscience and Public Health, Faculty of Veterinary Medicine, Chiang Mai University, Thailand https://orcid.org/0000-0003-0253-456X
Sittidet Mahasawangkul Elephant Hospital, National Elephant Institute, Forest Industry Organization, Hangchat, Lampang https://orcid.org/0000-0002-0311-2767
Chatchote Thitaram Faculty of Veterinary Medicine, Chiang Mai University, Thailand https://orcid.org/0000-0001-9319-5596
Ranida Quiggins Department of Anatomy, Faculty of Medicine, Chiang Mai University, Thailand https://orcid.org/0000-0002-4231-2892

Keywords:

comparative study, brain, elephant, human, tree shrew

Abstract

Objective This study was designed to compare elephant brain morphology and histology with that of humans and tree shrews.

Methods The size of elephant, human, and tree shrew brains were measured. Brains were sectioned and stained by the modified Mulligans for investigation of the ratios of gray matter and brain volume. The prefrontal gyrus and cerebellum were Nissl stained. The elephant cerebellum was prepared for Golgi staining.

Results The gyrification of the elephant cerebrum was found to be like similar to that of the human brain, but the gyrification of the tree shrew was not determined. The ratio of gray matter and brain volume of the elephant was less than that of both human and tree shrew brains. However, the olfactory bulbs and cerebellum of both the elephant and tree shrew were large. The cortical layers I-VI of the prefrontal cortex in both elephants and humans did not show a distinct layer IV. Additionally, elephant cortical neurons were larger than those found in humans. Purkinje neurons in the elephant cerebellum were uniquely shaped, having two main dendrites extending from the cell body.

Conclusions The elephant brain gyrification is similar to the human brain. However, it has large olfactory bulbs and cerebellum as does the tree shrew brain. The cortical and Purkinje cells in elephants are larger and more dendritically branched than those of humans.

References

Roger LJ, Kaplan G. Elephants That Paint, Birds That Make Music: Do Animals Have an Aesthetic Sense? Read CA, editor. The Dana Forum on Braain Science: Dana Press; 2006.

Roth G, Dicke U. Evolution of the brain andintelligence. Trends Cogn Sci. 2005;9:250-7.

Hakeem AY, Hof PR, Sherwood CC, Switzer RC 3rd, Rasmussen LE, Allman JM. Brain of the African elephant (Loxodonta africana): neuroanatomy from magnetic resonance images. Anat Rec A Discov Mol Cell Evol Biol. 2005;287:1117-27.

Jocobs B, Lubs J, Hannan M, Anderson K, Butti C, Sherwood CC, et al. Neuronal morphology in the African elephant (Loxodonta africana) neocortex. Brain Struct Funct. 2011;215:273-98.

Shoshani J, Kupsky WJ, Maarchant GH. Elephant brain Part I: Gross morphology, functions, comparative anatomy, and evolution. Brain Res Bull. 2006;70:124-57.

Kupsky WJ, Marchant GH, Cook K, Shoshani J, editors. Morphologic analysis of the hippocampal formation in Elephas maximus and Loxodonta africana with comparison to that of human. Rome: The World of Elephats; 2001.

Cao J, Yang EB, Su J-J, Li Y, Chow P. The tree shrews: Adjuncts and alternatives to primates as models for biomedical research. J Med Primatol. 2003;32:123-30.

Chomsung RD, Petry HM, Bickford ME. Ultrastructural examination of diffuse and specific tectopulvinar projections in the tree shrew. Comp Neurol. 2008;510:24-46.

Chomsung RD, Wei HJ, Day-Brown J, Petry H, Bickford H. Synaptic organization of connections between the temporal cortex and pulvinar nucleus of the tree shrew. Cereb Cortex. 2010;20:997-1011.

Cairό O. External measures of cognition. Front Hum Neurosci. 2011;5:108. doi: 10.3389/fnhum.2011.00108. PMID: 22065955; PMCID: PMC3207484.

Cozzi B, Spagnoli S, Bruno L. An overview of the central nervous system of elephant through a critical appraisal of the literature published in the XIX and XX centuries. . Brain Res Bull. 2001;54:219-27.

Thitaram C, Matchimakul P, Pongkan W, Tangphokhanon W, Maktrirat R, Khonmee J, et al. Histology of 24 organs from Asian elephant calves (Elephas maximus). PeerJ [Internet]. 2018. [cited 2022 Apr 6]. 6. Available from: https://doi.org/10.7717/peerj.4947.

Alston RL. A batch staining method for brain slices allowing volume measurements of grey and white matter using and Image Analyzing computer (Quantimer 720). Stain Technol. 1981;56:207-13.

Thongsopha C, Chaiwut T, Thaweekhotr P, Quiggins R, editors. Thunbergia laurifolia Lindl. extract maintains the straital dendritic spines in mouse models of Parkinson’s disease. Proceeding of the 42nd AAT Annual Conference; 2019 May 22 -24; Songkhla, Thailand, the Anatomy Association of Thailand; 2019. p. 46.

Herculano-Houzel S, Avelino-deSouza K, Neves K, Porfirio J, Messede D, Feijo JM, et al. The elephant brain in numbers. Front. Neuroanat. 2014;8:1-9.

Marino L, Hof PR. Nature’s Experiments in Brain Diversit. Anat Rec. 2005;278A:997-1000.

Maseko BC, Spocter MA, Haagensen M, Manerger PR. Elephants have relatively the largest cerebellum size of mammals. Anat Rec. 2012;295:661-72.

Maseko B, Jacobs B, Spocter M, Sherwood C, Manger P. Qualitative and quantitative aspects of the microanatomy of the African elephant cerebellar cortex. Brain Behav Evol. 2013;81:40-55.

Manager PR, Hemingway W, Haagensen M, Gilissen E. Cross-sectional area of the elephant corpus callosum: comparison to other eutherian mammals. Neuroscience. 2010;167:815-24.

Banker L, Tadi P. Neuroanatomy, Precentral Gyrus. [Updated 2021 Jul 31]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan. [cited 2022 Mar 31]. Available from: https://www.ncbi.nlm.nih.gov/books/NBK544218/.