Brain Made Transparent May Lead to Clearer Understanding

Scientists have developed a technique to make brains transparent, enabling them to see vast networks of neurons and structures for a big picture view of the organ that’s mostly studied in slices.

In a report published today in the journal Nature, researchers at Stanford University described the method that replaced fats in the brain of mice with a gel that made the organ transparent. The scientists were able to make images of the brain’s structures and see down to the cells and molecules, according to the paper.

The approach also was used on a human brain, the report said. Earlier this month, President Barack Obama announced the BRAIN Initiative, which will spend $100 million beginning in 2014 to map the complex interactions between neurons. The new technique may aid the research, allowing long-range circuits to be more easily mapped, said Michelle Freund, of the National Institute of Mental Health.

“The BRAIN Initiative recently announced by the White House is designed to facilitate innovative strategies to better understand the brain,” Freund said in a video released by the institute. “In order to do that, we need new technologies, and clarity is a great example of the type of technologies that will enable future brain studies.”

Previous methods required scientists to slice brains into small sections to look at anatomy. This slicing deformed the organs and made it difficult for researchers to see large-scale information running across the slices.

Fat Replacement

The researchers at Stanford near Palo Alto, California, replaced the fats that support the brain’s cells with a clear material that held all the delicate systems in place. First, the brains were soaked in a chemical bath and then heated, creating a clear gel in place of the fats. That allowed the scientists more access to the whole brains.

The team tested the technique, dubbed Clarity, on the brain of a mouse that had been genetically tweaked to produce a fluorescent protein. Under an electron microscope, the scientists were able to see even the spaces between the neurons.

What’s more, the researchers tested Clarity on the brain of an autistic person that had been preserved in formaldehyde for six years. There too, scientists saw individual nerve fibers. Since many brains have been preserved in formaldehyde for years, those organs stored in libraries may also be studied.