Research shows that the brains of all mammals show equal connectivity

Reviewed by Emily Henderson, B.Sc.July 20, 2020

Researchers at Tel Aviv University led by Professor Yaniv Assaf of the Department of Neurobiology, Biochemistry and Biophysics and Professor of the Sagole School of Neuroscience, Professor Yossi Yovel of the Faculty of Zoology, Sagole School of Neuroscience, and Steinhardt Nature Museum. We conducted the first such unique study designed to investigate brain connectivity in 130 mammals. Interesting results, contrary to widespread speculation, have revealed that brain connectivity levels are equal in all mammals, including humans.

We have found that brain connectivity, the efficiency of information transfer through neural networks, does not depend on a particular brain size or structure. In other words, the brains of all mammals, from small human-mediated mice to large bulls and dolphins, show equal connectivity and information travels among them with the same efficiency. We also found that the brain maintains this balance through a special compensation mechanism. If the connections between the hemispheres are high, the connections within each hemisphere are relatively low and vice versa.

Professor Yaniv Assaf, Department of Neurobiology, Tel Aviv University

Participants included researchers from the Kim Long Veterinary Institute in Beit Dagan, the Computer Science Department at TAU, and the Medical School at Technion. This paper Natural neuroscience June 8th.

“Brain connectivity is a core function and important for brain function,” explains Assaf. “Many scientists assume that the connectivity of the human brain is significantly higher than other animals, as a possible explanation for the superior functioning of “human animals.” “Major functions are conserved throughout the evolutionary process, so for example, all mammals have limbs.” In this project, brain connectivity indicates that major functions of this kind are important. I would like to explore the possibility that it is maintained in all mammals regardless of size or brain structure. For this, I used advanced research tools.”

The project began with an advanced diffuse MRI scan of the brain of about 130 mammals, each representing a different species. (All brain was removed from the dead animals, and the animals were not euthanized for the purposes of this study.) Brains obtained from the Kimron Veterinary Institute were found to weigh hundreds of kilograms from a small bat weighing 10 grams. Dolphin reaching even. The brains of about 100 of these mammals have never been MRI scanned, so this project created a new database that is globally unique. The brains of 32 living humans were similarly scanned. The unique technology of detecting white matter in the brain allowed researchers to reconstruct neural networks. The neurons through which information is transmitted, their axons (nerve fibers), and the synapses (junctions) they meet.

The next task was to compare scans of different animal types with vastly different brain sizes and structures. To this end, researchers used network theory, a tool in the branch of mathematics that allows to create and apply uniform gauges of brain conductivity. The number of summaries that a message must go through to get from one place in the neural network to another.

“The mammalian brain is made up of two hemispheres that are connected together by a set of nerve fibers (axons) that convey information,” Assaf explains. “For all brains we scanned, we measured four connection gauges: a connection at each hemisphere (intra-hemisphere connection), a connection between two hemispheres (between hemispheres), and a global connection. Has been found to be the same for all mammals: a small piece of information, including humans, that is, the information travels from one place to another via the same number of synapses. It must be said, that different brains use different strategies to maintain this equal measure, which is different throughout the brain: Weak connections within the hemisphere, others show the opposite. Yes.”

Professor Yovel describes another interesting finding. “We found that variations in connectivity compensation characterize not only different species, but different individuals within the same species,” he says. “In other words, some rat, bat, or human brains show higher interhemispheric connectivity at the expense of intrahemispheric connectivity, and vice versa. Compared to others of the same species. And it’s fascinating, because different types of brain connectivity can affect different cognitive functions and human abilities, such as sports, music, and math. Will be featured in.”

“Our research has revealed a universal law: preserving brain connections,” concludes Assaf. “This law shows that the efficiency of information transmission in neural networks in the brain is equal in all mammals, including humans. We also discovered a compensatory mechanism that balances brain connectivity in all mammals. This mechanism, perhaps revealed by some special talent (such as sports or music), is always counteracted by the relatively low connectivity of other parts of the brain. Investigate how the brain compensates for the enhanced connectivity associated with the process.”