Scientists at Washington University in St Louis reveal that human brain has at least 180 different regions, confirming the existence of 83 known regions and adding 97 new ones. Researchers describe how they combined scans of brain structure, function and connectivity to produce the new map, which confirmed the existence of 83 known brain regions and added 97 new ones. Some scans were taken while patients simply rested in the machine, while others were recorded as they performed a different task like maths, listening, organizing objects etc.
They published a spectacular new map of the brain, detailing nearly 100 previously unknown regions — an unprecedented glimpse into the machinery of the human mind.
They created the map by combining highly-detailed MRI scans from 210 healthy young adults who had agreed to take part in the Human Connectome Project, to understand how neurons in the brain are connected.
Researchers created the map with advanced scanners and computers running artificial intelligence programs that “learned” to identify the brain’s hidden regions from vast amounts of data collected from hundreds of test subjects, a far more sophisticated and broader effort than had been previously attempted.
“It’s a step towards understanding why we’re we,” said David Kleinfeld, a neuroscientist at the University of California, San Diego, who was not involved in the research.
“This map you should think of as version 1.0,” said Matthew F. Glasser, a neuroscientist at Washington University School of Medicine and lead author of the new research. “There may be a version 2.0 as the data get better and more eyes look at the data. We hope the map can evolve as the science progresses.”
“To understand the brain and to fix it, we really need to know the circuit diagram and all the parts, how they work and how they interact,” says McCormick, who did not take part in the study. “And this paper is a major advance toward understanding the circuit diagram.”
A map of myelin content (fatty insulation surrounding the brain’s nerves) in the left hemisphere of the cerebral cortex.
Putting together all that data helped identify these new areas. The cortex’s thickness, for instance, varies from brain region; in some places, it is as thin as 1mm and in others, as thick as 4.5mm. Overlaying that with imaging that reveals the brain’s blood flow, called fMRI, and adding information about the fatty insulation surrounding the brain’s nerves let the researchers create new boundaries for brain areas, says study co-author Matthew Glasser, a neuroscientist working on his MD at Washington University. Anywhere two of these things changed together in the brain was where the neural cartographers put a new boundary.
Using this method, the researchers divided the human brain into 180 cortical areas, including 97 new ones. One of these regions, for example, is a big groove called POS2 that’s right in front of the visual cortex, which is the part of the brain that allows you to see. The researchers identified the area by looking at the fMRI data and noticing that POS2 stayed deactivated when the subjects were solving a math problem but sprung into action when they relaxed. No one knows what it does, Glasser says. But that might be because no one’s known to look at it before. “What they found was about twice as many areas as was known, which is a huge leap in the neuroscience of human brain,” McCormick says.
Some, like Simon Eickhoff a neuropsychiatrist professor at Heinrich-Heine University Düsseldorf in Germany, dispute the novelty of these regions. For instance, some locations identified in today’s research had been documented before — just not in nearly as much detail. “I completely support the statement that they showed now in a systematic fashion, looking at the entire brain, using a multimodal approach, that there are subdivisions here and there and there,” he says. “But I would be careful about calling these areas completely new.”
The interpretation of fMRI data has also been called into question in other studies. The concern is that fMRIs can create false positives, skewing the statistical analysis researchers perform to identify the brain areas that are activated when performing particular tasks. But in this study, Glasser says, researchers made sure other features, such as cortex thickness and fatty insulation, corroborated the fMRI data before a new boundary was drawn. “One of the strengths of the study is that we’re making use of this corroboration,” Glasser says.
The pattern of brain activation (red, yellow) and deactivation (blue, green) in the left hemisphere when listening to stories while in the MRI scanner.
The map is mostly useful for future research efforts. The researchers trained a machine learning algorithm to be able to identify the fingerprints — like functions and connectivity — of the 180 cortical areas. Researchers will be able to use the algorithm to find the same areas in their own research subjects. The algorithm is for now 96.6 percent accurate — not good enough yet.
German neurologist Korbinian Brodmann first sliced and mapped the human brain more than a century ago he identified 50 distinct regions in the crinkly surface called the cerebral cortex that governs much of what makes us human.
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