James Gorman in the NYT:
Scientists at Stanford Universityreported on Wednesday that they have made a whole mouse brain, and part of a human brain, transparent so that networks of neurons that receive and send information can be highlighted in stunning color and viewed in all their three-dimensional complexity without slicing up the organ.
Even more important, experts say, is that unlike earlier methods for making the tissue of brains and other organs transparent, the new process, called Clarity by its inventors, preserves the biochemistry of the brain so well that researchers can test it over and over again with chemicals that highlight specific structures and provide clues to past activity. The researchers say this process may help uncover the physical underpinnings of devastating mental disorders like schizophrenia, autism,post-traumatic stress disorder and others.
The work, reported on Wednesday in the journal Nature, is not part of the Obama administration’s recently announced initiative to probe the secrets of the brain, although the senior author on the paper, Dr. Karl Deisseroth at Stanford, was one of those involved in creating the initiative and is involved in planning its future.
Dr. Thomas Insel, director of the National Institute of Mental Health, which provided some of the financing for the research, described the new work as helping to build an anatomical “foundation” for the Obama initiative, which is meant to look at activity in the brain.
Dr. Insel added that the technique works in a human brain that has been in formalin, a preservative, for years, which means that long-saved human brains may be studied. “Frankly,” he said, “that is spectacular.”
Kwanghun Chung, the primary author on the paper, and Dr. Deisseroth worked with a team at Stanford for years to get the technique right. Dr. Deisseroth, known for developing another powerful technique, called optogenetics, that allows the use of light to switch specific brain activity on and off, said Clarity could have a broader impact than optogenetics. “It’s really one of the most exciting things we’ve done,” he said, with potential applications in neuroscience and beyond.