Introducing the brain: definite patterns of neurons (Introduction)

by David Turell , Monday, January 01, 2024, 16:05 (325 days ago) @ David Turell

In all areas of brain and in many species studied:

https://www.sciencealert.com/neurons-in-the-brain-appear-to-follow-a-distinct-mathemati...

"Researchers taking part in the Human Brain Project have identified a mathematical rule that governs the distribution of neurons in our brains.

"The rule predicts how neurons are distributed in different parts of the brain, and could help scientists create precise models to understand how the brain works and develop new treatments for neurological diseases.

"In the wonderful world of statistics, if you consider any continuous random variable, the logarithm of that variable will often follow what's known as a lognormal distribution. Defined by the mean and standard deviation, it can be visualized as a bell-shaped curve, only with the curve being wider than what you'd find in a normal distribution.

"A team of researchers from the Jülich Research Center and the University of Cologne in Germany found the number of neurons in areas of the outer layer of neural tissue in different mammals fits a lognormal distribution.

"Mathematics aside, a simple and important distinction is the symmetry of the normal distribution bell curve and the asymmetry and heavy right-skewed tail of the lognormal distribution, due to a large number of small values and a few significantly large values.

***

"'The distribution of neuron densities influences the network connectivity," says neuroscientist Sacha van Albada of the Jülich Research Center.

"'For instance, if the density of synapses is constant, regions with lower neuron density will receive more synapses per neuron."

"The statistical distributions of neuron densities are still largely unknown, though research has certainly provided us with fascinating discoveries about our brain's cellular tissues.

***

"'Our results are in agreement with the observation that surprisingly many characteristics of the brain follow lognormal distributions," the authors write in their paper.

"A lognormal distribution is a natural result of processes that multiply, just like normal distribution is a natural result of adding up many independent variables.

***

"previous research suggests brain neural network variation is more than just a byproduct and may actively help animals learn in changing environments. And the fact that the same organization can be seen in different species and in most parts of the cortex suggests that the lognormal distribution is used for something." (my bold)

Comment: this distinctive distribution in so many species suggests it is convergent evolution, a concept that suggests a designer at work. The bold suggests my contention brains are designed to help us.