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