Two research teams will work to optimize MRI technology and trace volunteers’ connectomes.
NIH awarded grants totaling $40 million to two teams working to map the human brain’s connections in high resolution. One group will be led by researchers at Washington University, St. Louis and the University of Minnesota, Twin Cities. The other will be led by investigators at Massachusetts General Hospital (MGH)/Harvard University and the University of California Los Angeles (UCLA).
“On a scale never before attempted, this highly coordinated effort will use state-of-the-art imaging instruments, analysis tools, and informatics technologies, and all of the resulting data will be freely shared with the research community,” says Michael Huerta, Ph.D., of the National Institute of Mental Health, who directs the NIH Connectome initiative. “Individual variability in brain connections underlies the diversity of our thinking, perception, and motor skills, so understanding these networks promises advances in brain health.”
The Washington University/Minnesota team will map the connectomes in each of 1,200 healthy adults comprising twins and their siblings from 300 families. All-told, the $30 million five-year project will involve 33 collaborators from nine research centers including Oxford University, Indiana University, University of California, Berkeley, Warwick University in the U.K., University d’Annunzio in Italy, and the Ernst Strungmann Institute in Germany. Data will be made accessible via a customized Connectome Database Neuroinformatics Platform.
The maps will show the anatomical and functional connections between parts of the brain for each individual and will be related to behavioral test data. Comparing the connectomes and genetic data of genetically identical twins with fraternal twins will reveal the relative contributions of genes and environment in shaping brain circuitry and pinpoint relevant genetic variation. The maps will also shed light on how brain networks are organized.
To capture the brain’s anatomical wiring and its activity, both when participants are at rest and when challenged by tasks, researchers will use a customized MRI scanner with a magnetic field of 3 Tesla. This Connectome Scanner will incorporate new imaging approaches developed by consortium scientists at Minnesota and Advanced MRI Technologies and will provide 10-fold faster imaging times and better spatial resolution.
Additionally, a subset of twins will also be scanned using more powerful 7 and 10.5 Tesla MRI units at the University of Minnesota. For another subset of twins the scans will be complemented by movies of millisecond brain electrical activity obtained at St. Louis University, using magnetoencephalography (MEG) and electroencephalography.
Also collaborating with this larger project, the MGH/Harvard-UCLA Connectome consortium will focus on optimizing MRI technology for imaging the brain’s structural connections using diffusion MRI. The planned Connectome Scanner, to be built by Siemens Medical Systems for this project, will reportedly be the first in a new class of MRI instruments. It will boost resolving power while also shortening the scan times required to image each subject, says Bruce Rosen, M.D., Ph.D., who is co-directing the project with Van Wedeen, M.D., of MGH/Harvard and Arthur Toga, Ph.D., of UCLA.
“The MRI scanner system we are assembling will be four to eight times as powerful as conventional systems, enabling imaging of human neuroanatomy with much greater sensitivity than is currently possible,” explains Dr. Rosen.
Diffusion MRI, employed in both projects, maps the brain’s fibrous long-distance connections by tracking the motion of water. Different types of tissues are detectable by telltale water diffusion patterns characteristic of different types of cells. So the long extensions of neurons, called white matter, can been seen in sharp relief.
The MGH/Harvard team reports that it has pioneered the use of a diffusion MRI technique called diffusion spectrum imaging (DSI) to create maps of neural fibers crisscrossing the brain. DSI offers a higher resolution, more multidimensional view than an older technique called diffusion tensor imaging. This makes it possible, for example, to see the different orientations of multiple neural fibers that cross at a single location.
Supported by an $8.5 million grant over three years, the project will scan healthy adults, including some participants from the other consortia’s project. Data and research know-how will also be shared.
The grants are the first under the Human Connectome Project, which are being funded by 16 components of NIH under its Blueprint for Neuroscience Research program. The NIH Blueprint for Neuroscience Research is a cooperative effort among the NIH Office of the Director and the 15 NIH Institutes and Centers that support research on the nervous system.
“We’re planning a concerted attack on one of the great scientific challenges of the twenty-first century,” explains Washington University’s David Van Essen, Ph.D., who co-leads one of the groups with Minnesota’s Kamil Ugurbil, Ph.D. “The Human Connectome Project will have a transformative impact, paving the way toward a detailed understanding of how our brain circuitry changes as we age and how it differs in psychiatric and neurologic illness.”