A synaptic organizing principle for cortical neuronal groups [Neuroscience]

A synaptic organizing principle for cortical neuronal groups [Neuroscience]: "Neuronal circuitry is often considered a clean slate that can be dynamically and arbitrarily molded by experience. However, when we investigated synaptic connectivity in groups of pyramidal neurons in the neocortex, we found that both connectivity and synaptic weights were surprisingly predictable. Synaptic weights follow very closely the number of connections in a group of neurons, saturating after only 20% of possible connections are formed between neurons in a group. When we examined the network topology of connectivity between neurons, we found that the neurons cluster into small world networks that are not scale-free, with less than 2 degrees of separation. We found a simple clustering rule where connectivity is directly proportional to the number of common neighbors, which accounts for these small world networks and accurately predicts the connection probability between any two neurons. This pyramidal neuron network clusters into multiple groups of a few dozen neurons each. The neurons composing each group are surprisingly distributed, typically more than 100 μm apart, allowing for multiple groups to be interlaced in the same space. In summary, we discovered a synaptic organizing principle that groups neurons in a manner that is common across animals and hence, independent of individual experiences. We speculate that these elementary neuronal groups are prescribed Lego-like building blocks of perception and that acquired memory relies more on combining these elementary assemblies into higher-order constructs."

[Review] How to Grow a Mind: Statistics, Structure, and Abstraction

[Review] How to Grow a Mind: Statistics, Structure, and Abstraction: "

Authors: Joshua B. Tenenbaum, Charles Kemp, Thomas L. Griffiths, Noah D. Goodman"

200-300 bodies found in Japan's tsunami-hit Sendai

200-300 bodies found in Japan's tsunami-hit Sendai: "TOKYO: Around 200 to 300 bodies were found in a part of Japan's quake and tsunami hit Pacific coast town of Sendai, police said Friday according to media reports."

Alcoholic Beverages Induce Superconductivity

Alcoholic Beverages Induce Superconductivity: "

Wine can help keep conversation flowing at a dinner party. And now it looks like that wine may aid in materials science as well. Japanese researchers discovered that hot alcoholic beverages induce superconductivity in iron-based compounds.

 

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Why information can't be the basis of reality

Why information can't be the basis of reality: "

Is everything information? This seductive idea animates the brand-new book The Information by James Gleick (Pantheon 2011), which I just rave-reviewed in The Wall Street Journal . Gleick's book is, among other things, an in-depth biography of information theory, which the Bell Labs mathematician Claude Shannon invented in 1948 to provide a framework for improving the efficiency of communications.

A growing number of scientists, Gleick writes, are beginning to wonder whether information "may be primary: more fundamental than matter itself." This notion has inspired other recent books, including Programming the Universe by Seth Lloyd (Vintage 2007), Decoding the Universe by Charles Seife (Penguin 2007), Decoding Reality by Vlatko Vedral (Oxford 2010) and Information and the Nature of Reality , a collection of essays edited by Paul Davies (Cambridge 2010). But the everything-is-information meme violates common sense.

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