Google Earth for Brains? Scientists Zoom In With X-Rays to Make 3-D Maps of Brain Slices

Georgia Tech / ANL APS

The children of the Magic School Bus had the impossible opportunity to shrink down and zoom through parts of the body in all three dimensions. When it comes to the brain, a new study in eNeuro is offering the next (or next-next) best thing.

A group of researchers from several universities used a powerful X-ray to try and create 3-D maps of sections of mouse brains. The hope was to get a clearer picture of the brain at a level that scientists normally learn about by cutting through sliced samples of brain tissue.

F6 Georgia Tech/eNeuro

Neurons are surrounded by blood vessels and other supporting cells. Scientists have pretty solid means of looking at the brain at an extreme close up through electron microscopy, and at a wider view through fMRI, but a clear picture of the middle view complete with blood vessels and axons is harder to achieve.

So the researchers shot X-rays at samples of brain tissue. The X-rays were then passed through a crystal that converted them into physical light, and then captured by a camera. By rotating the samples as the X-rays shot through them, they were able to reconstruct 3-D images based off the brain slices.

Ciprian Ionita, a medical physicist at the University at Buffalo who was not involved in the study, called these images “exquisite.” The key thing here, Ionita says, is that the researchers were able to clearly distinguish nerve cells from blood vessels. While he’s seen similar approaches to getting close-up views of tissue samples from around the body, this is what impressed him.

“This kind of resolution, this kind of imaging can give you information about structures down the cellular level,” Ionita said.

But any fantasies of (at least visually) jumping on the Magic School Bus and zooming past glia and dendrites may be left unfulfilled. According to Ionita, there are limits that make this an unlikely path to reconstructing a picture of the whole brain.

Ionita lays out the obstacles in place: expense, the need for better developed computing technologies, and the challenges of applying X-ray to a human brain. The researchers are clear that this isn’t something they intend yet for clinical use. But Ionita added that he thinks this could be very useful for biopsies—a sample of tissue taken from a living person—down the road.

And in the meantime, for basic research, Ionita says, this imaging could be huge. For anyone working with smaller samples of brain tissue, according to Ionita, this new tool could be extremely useful. For example, Columbia University neuroscientist Rafael Yuste wrote to Newsweek that this kind of "out-of-the-box" approach could be extremely helpful in mapping neural circuits. 

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