Lifeboat Foundation

HBP researchers from Forschungszentrum Jülich and the University of Cologne (Germany) have uncovered how neuron densities are distributed across and within cortical areas in the mammalian brain. They have unveiled a fundamental organisational principle of cortical cytoarchitecture: the ubiquitous lognormal distribution of neuron densities.

Numbers of neurons and their spatial arrangement play a crucial role in shaping the brain’s structure and function. Yet, despite the wealth of available cytoarchitectonic data, the statistical distributions of neuron densities remain largely undescribed. The new HBP study, published in Cerebral Cortex, advances our understanding of the organisation of mammalian brains.

The team based their investigations on nine publicly available datasets of seven species: mouse, marmoset, macaque, galago, owl monkey, baboon and human. After analysing the cortical areas of each, they found that neuron densities within these areas follow a consistent pattern – a lognormal distribution. This suggests a fundamental organisational principle underlying the densities of neurons in the mammalian brain.

In their 1982 paper, Fredkin and Toffoli had begun developing their work on reversible computation in a rather different direction. It started with a seemingly frivolous analogy: a billiard table. They showed how mathematical computations could be represented by fully reversible billiard-ball interactions, assuming a frictionless table and balls interacting without friction.

This physical manifestation of the reversible concept grew from Toffoli’s idea that computational concepts could be a better way to encapsulate physics than the differential equations conventionally used to describe motion and change. Fredkin took things even further, concluding that the whole Universe could actually be seen as a kind of computer. In his view, it was a ‘cellular automaton’: a collection of computational bits, or cells, that can flip states according to a defined set of rules determined by the states of the cells around them. Over time, these simple rules can give rise to all the complexities of the cosmos — even life.

He wasn’t the first to play with such ideas. Konrad Zuse — a German civil engineer who, before the Second World War, had developed one of the first programmable computers — suggested in his 1969 book Calculating Space that the Universe could be viewed as a classical digital cellular automaton. Fredkin and his associates developed the concept with intense focus, spending years searching for examples of how simple computational rules could generate all the phenomena associated with subatomic particles and forces³.

SBUDNIC, built by an academically diverse team of students, was confirmed to have successfully reentered Earth’s atmosphere in August, demonstrating a practical, low-cost method to cut down on space debris.

When it comes to space satellites, getting the math wrong can be catastrophic for an object in orbit, potentially leading to its abrupt or fiery demise. In this case, however, the fiery end was cause for celebration.

About five years ahead of schedule, a small cube satellite designed and built by Brown University students to demonstrate a practical, low-cost method to cut down on space debris reentered Earth’s atmosphere sometime on Tuesday, Aug. 8 or immediately after—burning up high above Turkey after 445 days in orbit, according to its last tracked location from U.S. Space Command.

Human Brain Project researchers from Forschungszentrum Jülich and the University of Cologne (Germany) have uncovered how neuron densities are distributed across and within cortical areas in the mammalian brain. They have unveiled a fundamental organizational principle of cortical cytoarchitecture: the ubiquitous lognormal distribution of neuron densities.

Numbers of neurons and their spatial arrangement play a crucial role in shaping the brain’s structure and function. Yet, despite the wealth of available cytoarchitectonic data, the statistical distributions of neuron densities remain largely undescribed. The new Human Brain Project (HBP) study, published in the journal Cerebral Cortex, advances our understanding of the organization of mammalian brains.

Analyzing the datasets and the lognormal distribution.

Human Brain Project (HBP) researchers from Forschungszentrum Jülich and the University of Cologne (Germany) have uncovered how neuron densities are distributed across and within cortical areas in the mammalian brain. They have unveiled a fundamental organizational principle of cortical cytoarchitecture: the ubiquitous lognormal distribution of neuron densities.

Numbers of neurons and their spatial arrangement play a crucial role in shaping the brain’s structure and function. Yet, despite the wealth of available cytoarchitectonic data, the statistical distributions of neuron densities remain largely undescribed. The new HBP study, published in Cerebral Cortex, advances our understanding of the organization of mammalian brains.

The team based their investigations on nine publicly available datasets of seven species: mouse, marmoset, macaque, galago, owl monkey, baboon and human. After analyzing the cortical areas of each, they found that neuron densities within these areas follow a consistent pattern—a lognormal distribution. This suggests a fundamental organizational principle underlying the densities of neurons in the mammalian brain.

Mathematics has a reputation of being all about cold, calculating logic — but that couldn’t be further from the truth, says Eugenia Cheng.

Get ready for a lot of math…!

We have sort of an intuitive understanding of a big need in artificial intelligence and machine learning, which has to do with making sure that systems converge well, and that data is oriented the right way. Also, that we understand what these tools are doing, that we can look under the hood.

A lot of us have already heard of the term “curse of dimensionality,” but Tomaso Armando Poggio invokes this frightening trope with a good bit of mathematics attached… (Poggio is the Eugene McDermott professor in the Department of Brain and Cognitive Sciences, a researcher at the McGovern Institute for Brain Research, and a member of the MIT Computer Science and Artificial Intelligence Laboratory (CSAIL)

Sean Carroll is a theoretical physicist and philosopher who specializes in quantum mechanics, cosmology, and the philosophy of science. He is the Homewood Professor of Natural Philosophy at Johns Hopkins University and an external professor at the Sante Fe Institute. Sean has contributed prolifically to the public understanding of science through a variety of mediums: as an author of several physics books including Something Deeply Hidden and The Biggest Ideas in the Universe, as a public speaker and debater on a wide variety of scientific and philosophical subjects, and also as a host of his podcast Mindscape which covers topics spanning science, society, philosophy, culture, and the arts.

#physics #quantum #philosophy #mathematics.

Continue reading “Sean Carroll | The Many Worlds Interpretation & Emergent Spacetime | The Cartesian Cafe w Tim Nguyen” »

Everyone knows that arithmetic is true: 2 + 2 = 4.

But surprisingly, we don’t know why it’s true.

By stepping outside the box of our usual way of thinking about numbers, my colleagues and I have recently shown that arithmetic has biological roots and is a natural consequence of how perception of the world around us is organised.