Comparing canine brains using 3D-endocast modelling

October 22, 2020

Based on digital endocranial cast models the canine brain does not increase proportionally with body size. Researchers at ELTE Eötvös Loránd and Kaposvár University in Hungary reconstructed the surface morphology of 28 canine brains, including various dog breeds, wolves, coyotes, and jackals. The shortening of the facial skeleton greatly influences the ratio of certain brain regions, primarily the olfactory bulb and the frontal lobe. These changes might have profound implications for olfactory and problem-solving abilities.

Reconstructing the brain based on the internal surface patterns of a skull is a well-known method among archeologists studying the brains of extinct species, e.g. dinosaurs, mammoths and even cavemen. One way to achieve a model of the brain is to fill the endocranial space with specific gradually hardening fluids, and after the solidifying of the material the bones can be removed to reveal the cast, which reflects the surface of the brain with high fidelity. These are called endocranial casts, or endocasts.

Skull and endocast of a beagle. Video created by dr. Kálmán Czeibert: https://youtu.be/R7k-b-soVN4

Nowadays, rather than utilising endocasts, invasive process diagnostic imaging techniques are highly preferred. Computer tomography (CT) is the best and easiest way to visualize the bones, with all of their external and internal structures and composition. Using CT is also advantageous in endocranial analysis, as researchers can create virtual endocasts based on the digitized skulls. This allows for a higher freedom during examinations, because these virtual models can be rotated, colorized, cut, and completed. They can be shown not only on mobile phones, tablets or computers, but with the help of 3D-printing technology one can replicate them in the requested number and scale as well.

This digital endocasting technique was used by researchers from ELTE who scanned skulls from the collection of dr. Tibor Csörg? (ELTE, Department of Anatomy, Cell and Developmental Biology), which comprises almost 400 dog skulls from 152 canine breeds. "Due to the high resolution scanning, detailed 3D models could be created. This means that not only the main convolutions, that is, the cerebral gyri, can be recognized on the final model, but the location of the major blood vessels can also be seen on the surface." - explains dr. Kálmán Czeibert, veterinarian and postdoctoral researcher at the Senior Family Dog Project, first author of the publication. "We compared the shape, volume and surface features of the endocasts from 28 specimens in our recent study in Frontiers in Veterinary Science. These models clearly show how the shortening of the facial part of the skull affected the morphology of the brain, distorting the olfactory bulb, which is pushed back and underneath the frontal lobe in certain breeds (like the French bulldog or pug), changing the ratio between the cerebral areas."

In order to clarify how this change affects dogs' olfactory and cognitive performance, further imaging and behavioral investigations are needed. The new collection is part of the Canine Brain and Tissue Bank at ELTE, funded by a European Research Council (ERC) grant. The bank will help researchers to link the brain with behaviour. "In some areas, where volume has diminished, neuronal density and the relationship with other brain regions may act to counteract these changes. To further examine these speculations, behavioural testing, diagnostic imaging (like CT, MR or EEG), and histological and molecular assessment will be needed." - said dr. Enik? Kubinyi, senior researcher at ELTE, principal investigator of the research group.

"One of our primary aims was the widespread dissemination of scientific knowledge.' - adds dr. Czeibert. "How dog skulls and brains vary is striking. For example, despite the 30-fold difference in body weight between a Neapolitan mastiff and a chihuahua, their endocasts' volumes have only a 2-fold difference." The researchers from ELTE plan to increase the number of skulls by digitizing more specimens for microevolutionary studies in the framework of an international cooperation.
-end-
Original study: Czeibert, K., Sommese, A., Petneházy, Ö., Csörg?, T., Kubinyi, E.: Digital endocasting in comparative canine brain morphology, Frontiers in Veterinary Science. 7. 2020. https://doi.org/10.3389/fvets.2020.565315

The research was supported by "Cognitive Ageing in Dogs" starting grant (EVOLOR 680040) of the European Research Council (ERC).

Eötvös Loránd University (ELTE), Faculty of Science

Related Brain Articles from Brightsurf:

Glioblastoma nanomedicine crosses into brain in mice, eradicates recurring brain cancer
A new synthetic protein nanoparticle capable of slipping past the nearly impermeable blood-brain barrier in mice could deliver cancer-killing drugs directly to malignant brain tumors, new research from the University of Michigan shows.

Children with asymptomatic brain bleeds as newborns show normal brain development at age 2
A study by UNC researchers finds that neurodevelopmental scores and gray matter volumes at age two years did not differ between children who had MRI-confirmed asymptomatic subdural hemorrhages when they were neonates, compared to children with no history of subdural hemorrhage.

New model of human brain 'conversations' could inform research on brain disease, cognition
A team of Indiana University neuroscientists has built a new model of human brain networks that sheds light on how the brain functions.

Human brain size gene triggers bigger brain in monkeys
Dresden and Japanese researchers show that a human-specific gene causes a larger neocortex in the common marmoset, a non-human primate.

Unique insight into development of the human brain: Model of the early embryonic brain
Stem cell researchers from the University of Copenhagen have designed a model of an early embryonic brain.

An optical brain-to-brain interface supports information exchange for locomotion control
Chinese researchers established an optical BtBI that supports rapid information transmission for precise locomotion control, thus providing a proof-of-principle demonstration of fast BtBI for real-time behavioral control.

Transplanting human nerve cells into a mouse brain reveals how they wire into brain circuits
A team of researchers led by Pierre Vanderhaeghen and Vincent Bonin (VIB-KU Leuven, Université libre de Bruxelles and NERF) showed how human nerve cells can develop at their own pace, and form highly precise connections with the surrounding mouse brain cells.

Brain scans reveal how the human brain compensates when one hemisphere is removed
Researchers studying six adults who had one of their brain hemispheres removed during childhood to reduce epileptic seizures found that the remaining half of the brain formed unusually strong connections between different functional brain networks, which potentially help the body to function as if the brain were intact.

Alcohol byproduct contributes to brain chemistry changes in specific brain regions
Study of mouse models provides clear implications for new targets to treat alcohol use disorder and fetal alcohol syndrome.

Scientists predict the areas of the brain to stimulate transitions between different brain states
Using a computer model of the brain, Gustavo Deco, director of the Center for Brain and Cognition, and Josephine Cruzat, a member of his team, together with a group of international collaborators, have developed an innovative method published in Proceedings of the National Academy of Sciences on Sept.

Read More: Brain News and Brain Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.