The researchers discovered that our brain’s cortex, or outer mantle, is composed of 180 distinct areas per hemisphere. For example, the image above shows areas connected to the three main senses – hearing (red), touch (green) vision (blue) and opposing cognitive systems (light and dark). The map is based on data from resting state fMRI scans performed as part of the Human Connectome Project. [Matthew Glasser, Ph.D., and David Van Essen, Ph.D., Washington University]
The researchers discovered that our brain’s cortex, or outer mantle, is composed of 180 distinct areas per hemisphere. For example, the image above shows areas connected to the three main senses – hearing (red), touch (green) vision (blue) and opposing cognitive systems (light and dark). The map is based on data from resting state fMRI scans performed as part of the Human Connectome Project. [Matthew Glasser, Ph.D., and David Van Essen, Ph.D., Washington University]

The cortex or outer mantle of the human brain consists of 180 distinct areas per hemisphere—more than twice the number previously known to researchers—according to a just-published study.

Using software that mapped the “fingerprint” of each of these areas in an individual’s brain scans, the new study identified, with a nearly 97% detection rate, 97 new cortex areas per hemisphere.

The study also confirmed 83 previously known areas, the NIH said yesterday. Until now, the most widely known brain map was the one published in 1909 by German Neurologist Korbinian Brodmann that showed 52 regions or “Brodmann’s areas” per hemisphere.

While some cortex areas were atypically located in a small number of subjects, the data-derived algorithms incorporated into the software were nevertheless able to map them successfully.

“These new insights and tools should help to explain how our cortex evolved and the roles of its specialized areas in health and disease, and could eventually hold promise for unprecedented precision in brain surgery and clinical work-ups,” stated Bruce Cuthbert, Ph.D., acting director of NIH’s National Institute of Mental Health (NIMH), which co-funded the research as part of NIH’s Human Connectome Project (HCP).

Two NIMH grantees—David Van Essen, Ph.D., and Matthew Glasser, Ph.D., of Washington University in St. Louis—joined with colleagues at six other research centers to report on their discoveries in the study, published yesterday in Nature (“A Multi-Modal Parcellation of Human Cerebral Cortex”).

The HCP team used multiple, precisely aligned, magnetic resonance imaging (MRI) modalities to measure cortical architecture, activity, connectivity, and topography in a group of 210 healthy participants. These measures—which included cortex thickness, cortex myelin content, and task and resting-state functional MRI (fMRI)—cross-validated each other. Researchers then confirmed their findings in an additional independent sample of 210 healthy participants.

The measures used by researchers contrasted with earlier studies of cortex organization, which often used just one measure, such as examining postmortem tissue with a microscope. The resulting, often uncertain, delineation of cortex areas sometimes led to shaky comparability of brain imaging findings, according to the NIH.

Some cortex areas may have further subdivisions or be subunits of other areas, said Dr. Van Essen, the study’s senior author.

Added Dr. Glasser: “The ability to discriminate individual differences in the location, size, and topology of cortical areas from differences in their activity or connectivity should facilitate understanding of how each property is related to behavior and genetic underpinnings.”

While the study included fMRI scans of subjects performing tasks, the researchers determined that resting-state MRI techniques should suffice to map the areas in future studies using the tools they developed.

The “areal classifier” and related tools are being shared with researchers through HCP’s website, while the data behind each published figure is available through an NIH-funded database developed by Dr. Van Essen’s lab.








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