{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,10]],"date-time":"2026-07-10T22:08:03Z","timestamp":1783721283028,"version":"3.55.0"},"reference-count":45,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,3,27]],"date-time":"2026-03-27T00:00:00Z","timestamp":1774569600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Neurol."],"abstract":"<jats:sec>\n                    <jats:title>Introduction<\/jats:title>\n                    <jats:p>\n                      Australia\u2019s native fauna is unique through millions of years of isolated evolution resulting in a significant divergence of marsupial brain anatomy, and thus neural pathways, from eutherian mammals. This study provides a morphometric description of a mature female koala (\n                      <jats:italic>Phascolarctos cinereus<\/jats:italic>\n                      ) through segmentation of high-resolution magnetic resonance images. As the availability of brain specimens of the endangered koala is scarce, brain segmentation has been performed on a single specimen.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>\n                      The brain of a naturally deceased koala was removed and fixed in 10% neutral buffered formaldehyde (pH 7.0). The MRI was acquired on a 9.4\u202fT Bruker Biospec MR system with Paravision 7.0 software, using a 3D multigradient echo sequence, with TR\/TE\u202f=\u202f70\u202fmsec\/ (8 echoes 4\u201332\u202fmsec), a field of view\u202f=\u202f7.0 \u00d7 6.4 \u00d7 4.0\u202fcm\n                      <jats:sup>3<\/jats:sup>\n                      . AMIRA post image processing software was used to create three-dimensional volume reconstruction of different brain structures, allowing for the calculation of their volumes.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>\n                      The koala brain is lissencephalic and has a volume of 15720.98\u202fmm\n                      <jats:sup>3<\/jats:sup>\n                      . It was found that the olfactory bulbs of the koala were 418\u202fmm\n                      <jats:sup>3<\/jats:sup>\n                      or 2.66% of the total brain volume (tbv). The cerebral hemispheres were 9336.92\u202fmm\n                      <jats:sup>3<\/jats:sup>\n                      (59.39% of the tbv). The interhemispheric connections were 148\u202fmm\n                      <jats:sup>3<\/jats:sup>\n                      (0.94% of tbv). The combined volume of the anterior commissure and fasciculus aberrans, which is specific to marsupials, has also been labeled and segmented. The ventricular system was 172\u202fmm\n                      <jats:sup>3<\/jats:sup>\n                      (1.09% of tbv). The brainstem was 1874\u202fmm\n                      <jats:sup>3<\/jats:sup>\n                      (11.92% of tbv). The cerebellum was 2304.69\u202fmm\n                      <jats:sup>3<\/jats:sup>\n                      (14.66% of tbv).\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion<\/jats:title>\n                    <jats:p>This study can be used as a basis for clinical imaging of koalas and as baseline data for future research into brain development of koalas and other marsupials.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.3389\/fneur.2026.1733030","type":"journal-article","created":{"date-parts":[[2026,3,27]],"date-time":"2026-03-27T14:12:06Z","timestamp":1774620726000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":2,"title":["Description of the koala (Phascolarctos cinereus) brain based on magnetic resonance images"],"prefix":"10.3389","volume":"17","author":[{"given":"Kristy R. Q.","family":"Goh","sequence":"first","affiliation":[{"name":"Sydney School of Veterinary Science, The University of Sydney","place":["Camperdown, NSW, Australia"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Natasha B.","family":"Anthoniel","sequence":"additional","affiliation":[{"name":"Sydney School of Veterinary Science, The University of Sydney","place":["Camperdown, NSW, Australia"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Timothy","family":"Stait-Gardner","sequence":"additional","affiliation":[{"name":"Nanoscale Organisation and Dynamics Group, School of Science, Western Sydney University","place":["Penrith, NSW, Australia"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nyoman D.","family":"Kurniawan","sequence":"additional","affiliation":[{"name":"Australian Institute for Bioengineering and Nanotechnology, Centre for Advanced Imaging, The University of Queensland","place":["Brisbane, QLD, Australia"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Marianne D.","family":"Keller","sequence":"additional","affiliation":[{"name":"Sydney School of Veterinary Science, The University of Sydney","place":["Camperdown, NSW, Australia"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2026,3,27]]},"reference":[{"key":"ref1","doi-asserted-by":"publisher","first-page":"900","DOI":"10.3390\/biology11060900","article-title":"Comparative study of brain size ontogeny: marsupials and placental mammals","volume":"11","author":"De Miguel","year":"2022","journal-title":"Biol"},{"key":"ref2","doi-asserted-by":"publisher","first-page":"243","DOI":"10.1071\/AM06034","article-title":"MR imaging of brain morphology, vascularisation and encephalization in the koala","volume":"28","author":"Taylor","year":"2006","journal-title":"Aust Mammal"},{"key":"ref3","author":"Ashwell","year":"2024"},{"key":"ref4","first-page":"61","volume-title":"The Neurobiology of Australian Marsupials: brain Evolution in the other Mammalian Radiation","author":"Ashwell","year":"2010"},{"key":"ref5","doi-asserted-by":"publisher","first-page":"2188","DOI":"10.1002\/cne.25328","article-title":"Magnetic resonance imaging and diffusion tensor imaging reconstruction of connectomes in a macropod, the quokka (Setonix brachyurus)","volume":"530","author":"Kariyappa","year":"2022","journal-title":"J Comp Neurol"},{"key":"ref6","volume-title":"The rat brain in Stereotaxic Coordinates","author":"Paxinos","year":"2005"},{"key":"ref7","doi-asserted-by":"publisher","first-page":"e0155974","DOI":"10.1371\/journal.pone.0155974","article-title":"Development and implementation of a Corriedale ovine brain atlas for use in atlas-based segmentation","volume":"11","author":"Liyanage","year":"2016","journal-title":"PLoS One"},{"key":"ref8","doi-asserted-by":"crossref","first-page":"226","DOI":"10.1098\/rspl.1902.0022","article-title":"On a peculiarity of the cerebral commissures in certain Marsupialia, not hitherto recognised as a distinctive feature or the Diprotodontia","volume":"70","author":"Smith","year":"1902","journal-title":"Proc R Soc Lond"},{"key":"ref9","doi-asserted-by":"publisher","first-page":"347","DOI":"10.1007\/978-1-4939-7531-0_21","article-title":"MRI in the study of animal models of neurodegenerative diseases","volume":"1718","author":"Kurniawan","year":"2018","journal-title":"Methods Mol Biol"},{"key":"ref10","volume-title":"AMIRA (Version 6) [Software]","year":"2015"},{"key":"ref11","doi-asserted-by":"publisher","first-page":"50","DOI":"10.1016\/j.semcdb.2021.04.009","article-title":"The evolution, formation and connectivity of the anterior commissure","volume":"118","author":"Fenlon","year":"2021","journal-title":"Semin Cell Dev 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