Introducing the brain: mammal connectivity (Introduction)

by David Turell , Monday, July 20, 2020, 19:17 (1587 days ago) @ David Turell

All mammals have the same connectivity:

https://medicalxpress.com/news/2020-07-mri-scans-brains-mammals-humans.html

"Researchers at Tel Aviv University, led by Prof. Yaniv Assaf...conducted a first-of-its-kind study designed to investigate brain connectivity in 130 mammalian species. The intriguing results, contradicting widespread conjectures, revealed that brain connectivity levels are equal in all mammals, including humans.

"'We discovered that brain connectivity—namely the efficiency of information transfer through the neural network—does not depend on either the size or structure of any specific brain," says Prof. Assaf. "In other words, the brains of all mammals, from tiny mice through humans to large bulls and dolphins, exhibit equal connectivity, and information travels with the same efficiency within them. We also found that the brain preserves this balance via a special compensation mechanism: when connectivity between the hemispheres is high, connectivity within each hemisphere is relatively low, and vice versa."

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"'A mammal's brain consists of two hemispheres connected to each other by a set of neural fibers (axons) that transfer information," Prof. Assaf explains. "For every brain we scanned, we measured four connectivity gages: connectivity in each hemisphere (intrahemispheric connections), connectivity between the two hemispheres (interhemispheric), and overall connectivity. We discovered that overall brain connectivity remains the same for all mammals, large or small, including humans. In other words, information travels from one location to another through the same number of synapses. It must be said, however, that different brains use different strategies to preserve this equal measure of overall connectivity: some exhibit strong interhemispheric connectivity and weaker connectivity within the hemispheres, while others display the opposite."

"Prof. Yovel describes another interesting discovery. "We found that variations in connectivity compensation characterize not only different species but also different individuals within the same species," he says. "In other words, the brains of some rats, bats, or humans exhibit higher interhemispheric connectivity at the expense of connectivity within the hemispheres, and the other way around—compared to others of the same species. It would be fascinating to hypothesize how different types of brain connectivity may affect various cognitive functions or human capabilities such as sports, music or math.

"'Our study revealed a universal law: Conservation of Brain Connectivity," Prof. Assaf concludes. "This law denotes that the efficiency of information transfer in the brain's neural network is equal in all mammals, including humans. We also discovered a compensation mechanism which balances the connectivity in every mammalian brain. This mechanism ensures that high connectivity in a specific area of the brain, possibly manifested through some special talent (e.g. sports or music) is always countered by relatively low connectivity in another part of the brain."

Comment: I assume our difference is in the number of operational neuron networks.