If you ask a neuroscientist to show you a map of the brain, chances are they’ll pick one that’s more than a century old.
In 1909, a German anatomist named Korbinian Brodmann published an intricate map of the brain’s surface. He painstakingly stained brain cells of many kinds to find the anatomical features that set them apart and the rules that governed their layered organization. We now know that neurons that sense a touch on the skin are found in Brodmann area 1; those allowing you to read this article sit in area 17.
Now, scientists have built an updated map of the brain that further refines those areas. Published Wednesday in the journal Nature, the map reveals 97 previously unknown areas of the brain’s surface (the cortex), in addition to 83 areas that were described before.
Unlike Brodmann’s and other brain maps built using just one property (how the cells looked under a microscope, for example), the new atlas is made by combining several types of data that capture multiple properties of these brain areas: their anatomy, their function and the connections between them.
The data was gathered using multiple non-invasive brain imaging measures from 210 people in the NIH Human Connectome Project, and the accuracy of the resulting map was confirmed on another group of 210 people.
The study authors hope that “researchers who have previously used Brodmann’s map to identify brain areas will use this new map from the Human Connectome Project instead,” said Matthew Glasser of Washington University in St. Louis, the study’s lead author.
According to Glasser and his colleagues at six other research centers, combining anatomical data with functional data from fMRI brain scans has allowed for more precise delineation between brain areas.
For example, an area that may look indistinguishable from its neighbor under the microscope or on MRI scans may light up on fMRI scans that measure brain activation during a specific mental task and thus stand out as a distinct region.
“The situation is analogous to astronomy where ground-based telescopes produced relatively blurry images of the sky before the advent of adaptive optics and space telescopes,” Glasser said in a press release.
Researchers hope that a more precise division of the brain can prevent potential confusion in neuroscience studies that may be looking at overly broad areas ― and lead to new discoveries.
The map is a “long-awaited advance,” said B. T. Thomas Yeo and Simon Eickhoff, two neuroscientists not involved in the study, in an accompanying article in Nature. They added that it creates a reference atlas that allows neuroscientists studying various aspects of the brain to work within a common framework.
This article has been updated to include a comment from Matthew Glasser.