Stanford scientists have developed a technique that lets them turn a brain completely transparent — without causing any damage at all to its structure. So far, the scientists have turned mouse and fish brains transparent, and they've also shown that the process works with bits of human brain too.
It's worth pointing out that, sadly, the brain has to be removed from the body before the process can be undertaken, but whatever — it's an amazing and quirky advance.
The image above shows an original mouse brain on the left, and then on the right two days later, following treatment. The researchers explain how it works:
This new form is created by replacing the brain's lipids with a hydrogel. The hydrogel is built from within the brain itself in a process conceptually similar to petrification, using what is initially a watery suspension of short, individual molecules known as hydrogel monomers. The intact, postmortem brain is immersed in the hydrogel solution and the monomers infuse the tissue. Then, when "thermally triggered," or heated slightly to about body temperature, the monomers begin to congeal into long molecular chains known as polymers, forming a mesh throughout the brain. This mesh holds everything together, but, importantly, it does not bind to the lipids. With the tissue shored up in this way, the team is able to vigorously and rapidly extract lipids through a process called electrophoresis. What remains is a 3-D, transparent brain with all of its important structures - neurons, axons, dendrites, synapses, proteins, nucleic acids and so forth - intact and in place.
While it might sound merely like a neat party trick, it's actually an incredibly useful finding: it finally allows the entire 3D structure of the brain to be studied with visible light and chemical markers, without having to cut it up. That means the researchers can create incredibly detailed maps of the brain, because visible light microscopy is inherently more accurate than imaging techniques like MRI. In the process, the researchers are learning more about the brain's structure and function — to such an extent that they're already a little worried about what to do with all the data the technique is creating. Sounds like a challenge. [Stanford via Boing Boing]