Thursday, April 11, 2013

Scientists create phantom sensations in non-amputees

The sensation of having a physical body is not as self-evident as one might think. Almost everyone who has had an arm or leg amputated experiences a phantom limb: a vivid sensation that the missing limb is still present. A new study by neuroscientists at the Karolinska Institutet in Sweden shows that it is possible to evoke the illusion of having a phantom hand in non-amputated individuals. (Journal of Cognitive Neuroscience)

Ph.D. Student Arvid Guterstam explains how he and his colleagues at Karolinska Institutet in Sweden can evoke the illusion of having a phantom hand in non-amputated individuals. (Credit: Ola Danielsson, Karolinska Institutet)

Wednesday, April 10, 2013

New technique for making the brain (and other organs) transparent

Wow, Karl Deisseroth and his Stanford-team did it again: inventing a new technique to study the brain.

In 2005 it was optogenetics, now it's CLARITY, a technique to turn the brain from a "mysterious black box" into something transparent. CLARITY allows scientists to see both the fine details and the big picture of the brain at the same time.

Watch here post-mortem brains of a mouse, and of a 7 year old boy who suffered from autism:

Published in this week's edition of the journal Nature (april 10, 2013):

"A method for making organs transparent, which could enable deep imaging of large-scale intact biological systems, is described online in Nature this week. High-resolution imaging of biological tissue has traditionally required sectioning, but this results in a loss of long-range connectivity in the case of brains. Demonstration of the new technique in mouse brains picks up both long-range circuit projections and local circuit wiring, among other details.

Obtaining detailed structural and molecular information from intact, complex biological systems has been a long-standing challenge. Karl Deisseroth and colleagues [Stanford University] have developed a technique that they call CLARITY to make full, intact organs optically transparent, while maintaining structural and molecular integrity, by soaking them in acrylamide. Using this technique in mice, the researchers were able to perform intact tissue imaging of a range of structures, signalling molecules and cellular relationships. They also show that CLARITY can be used to analyse clinical samples and may provide a means for probing structural and molecular underpinnings of physiological function and disease."

Remove the brain's fat, replace it by clear and permeable high-tech cocktail (that holds everything else in place) and suddenly the brain becomes transparent:

                            Credit: Kwanghun Chung and Karl Deisseroth, Howard Hughes Medical Institute/Stanford University

Saturday, April 6, 2013

Alan Turing vs. Garry Kasparov

During the conference Turing100@Manchester (june 2012) Garry Kasparov played a chess game against Alan Turing's very first computer chess program Turochamp (written around 1950).

Watch here the game of 16 moves (Turochamp plays with white, Kasparov with black):

This is what Kasparov said about the first computer chess program:

“I suppose you might call it primitive, but I would compare it to an early car – you might laugh at them but it is still an incredible achievement.”

“He wrote algorithms without having a computer – many young scientists would never believe that was possible. It was an outstanding accomplishment.”

“Although it’s only thinking two moves ahead, I would have thought it would give the amateur player some serious problems.”

“Alan Turing is one of the very few people about who you could say that if he had lived longer the world would be a different place.”