New brain areas mapped

Katrin Amunts and her colleagues at the Research Centre Jülich in Germany are explorers. Explorers of the brain — striking out and finding new territories; rewriting and adding to our brain maps.

What, you thought we’d already got a map of the brain? “We have not got a complete map, and there is no such thing as a single map of the brain,” says Amunts. With major collaborator Karl Zilles, and joined by a host of keen-eyed lab members, over the past 20 years she’s been working on a project to map the brain in fine detail and using a variety of methods.

At a talk in the neuroanatomy session here at the annual meeting of the Organization for Human Brain Mapping (OHBM), Amunts’ colleague Sebastian Bludau reported the discovery of two brain areas. They’re at the very front of the brain, in a region called the frontal pole that we know is involved in such tasks as processing social information and working memory. He has christened them FP1 and FP2.

Of course, we already knew that the frontal pole was there. In the early 1900s, a neuroscientist called Korbinian Brodmann gave it the name ‘Area 10′ when he published a series of maps of the brain based on his painstaking explorations under the microscope. He looked at the ways cells differed through the brain and delineated areas on the basis of their cells.

But Brodmann’s Area 10 was rather large. Recent studies suggested there was more going on within it, Amunts says. Studies of brain function reported that the lateral half, on the outside surface of the brain, was active when people use working memory, whereas a region tucked into a fold on the inside dealt with social cognition and emotion processing.

To map the anatomy in finer detail, Bludau took ten post-mortem brains and sliced them extremely thinly — into 20-micrometre slices — before looking at them under the microscope and analysing them digitally. His work revealed a sharp distinction between the cells in the outer and inner parts. Overlapping this with functional information gave a pleasing match.

The task was daunting, but worth it. “It’s a very time-consuming process. For the frontal pole it took two, maybe three years,” says Bludau, looking relieved to have finished. “Every time it’s like a new continent, and it’ surprising to find more and more areas,” Amunts adds.

The team cannot rest on its laurels though. Amunts tells me that there are 150, maybe 200, separate areas of the brain. She hopes that in the next five years her team will have put most of them on the map.