FOR IMMEDIATE RELEASE
August 29, 2011
Contact: Donna Krupa
Office: (301) 634-7209
dkrupa@the-aps.org
@Phyziochick
Brain Mapping Technique Reveals More About Vast, Interconnected Networks
Certain regions, such as the sensory and motor cortices, found to be confined to small geographic areas
Bethesda, Md. (Aug. 29, 2011)—Researchers have worked for decades to identify regions of the brain responsible for various behaviors. For example, animal experiments and brain injuries in humans have revealed areas that control vision, speech and voluntary motion. However, more recent research suggests that these areas don’t operate in isolation and that they, and other regions, are interconnected with other areas that are often considerable distances away. To shed light on these networks and the cross-talk that occurs between different brain regions, a team of researchers from Harvard University and Massachusetts General Hospital used a technique called functional connectivity MRI (fcMRI) to identify which parts of the brain coordinate certain activities.
The article is entitled, “The Organization of the Human Cerebral Cortex Estimated by Functional Connectivity.” It appears in the Articles in PresS section of the American Journal of Physiology – Regulatory, Integrative, and Comparative Physiology, published by the American Physiological Society.
Methodology
The research team performed fcMRIs on 1,000 healthy adults between the ages of 18 and 35. The technique involved collecting brain scans on subjects in a functional MRI machine, which identifies brain activity by tracking blood flow. For several minutes, participants lay in the scanner while the researchers collected electronic data. A subset of the participants received brain scans while watching simple images on a screen, such as a clockwise rotating wedge or an expanding ring. The researchers analyzed all collected data using software to track which regions of the brain were active in conjunction with other areas.
Results: Small vs. Wide Areas of Connectivity
The findings showed that some regions, such as the sensory and motor cortices, have strong local connectivity, meaning that the networks were confined to small geographic areas. These networks showed hierarchical patterns of connectivity, with some areas activating first and leading to a cascade of communication with other areas. In contrast, the remainder of the cortex outside these primary areas—a broad swath known as the association cortex—displayed more widely distributed networks. These networks were more likely to operate in parallel, with equal cross-talk between regions, rather than in a hierarchical fashion.
Importance of the Findings
These findings provide a comprehensive foundation to inform future functional brain studies. They also shed light on evolution of the human brain in comparison to our closest primate relatives. The human cerebral cortex, especially the association cortex, is many times the size of other mammalian species. But rather than being simply a “higher-order” version of other animals’ brains, the human brain appears to have a different organization. Understanding how various brain regions are functionally connected could help explain how humans’ brains evolved.
“Methods that can measure connectivity may provide novel insight into the organization of distributed brain systems,” the authors say.
Study Team
Dr. Randy L. Buckner of Harvard University, Department of Psychology, Center for Brain Science, Cambridge, MA led the study along with his colleagues in the department, B.T. Thomas Yeo, Fenna M. Krienen, Jorge Sepulcre, and Marisa Hollinshead; Mert R. Sabuncu, Lilla Zöllei, Jonathan R. Polimei, Bruce Fischl and Hesheng Liu, of the Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA; Danial Lashkari, with the Computer Science and Artificial Intelligence Lab, Massachusetts Institute of Technology; Cambridge; Joshua L. Roffman, of the Department of Psychiatry, Massachusetts General Hospital, Boston; and Jordan W. Smoller, with the Center for Human Genetics Research, Massachusetts General Hospital, Boston.
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NOTE TO EDITORS: The abstract and article are available online. To interview Dr. Buckner, please contact Donna Krupa at dkrupa@the-aps.org, 301.634.7209.
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Physiology is the study of how molecules, cells, tissues and organs function to create health or disease. The American Physiological Society (APS; www.the-APS.org/press) has been an integral part of the discovery process since it was established in 1887. To keep up with the science, follow @Phyziochick on Twitter.
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