A commonly used brain scanning technique can map electrical activity under the skull as precisely as more invasive methods that rely on probes or electrodes, researchers at Vanderbilt University Medical Center (VUMC) reported this month.
The study supports the potential usefulness of the technique, a version of functional magnetic resonance imaging (fMRI), for diagnosing and monitoring treatment of brain injuries, tumors and conditions ranging from epilepsy to psychiatric disorders, the researchers said.
The study in animals, published this month in the Proceedings of the National Academy of Sciences, “validates the use of high-field, high-resolution fMRI as a mapping tool to tell where things are happening,” said senior author John Gore, Ph.D., director of the Vanderbilt University Institute of Imaging Science.
The scanning technique detects blood oxygenation level-dependent (BOLD) signal changes related to oxygen levels in the blood. Previously these changes were considered to be indirect measures of neuronal activity in the brain.
The Vanderbilt study found that fMRI “actually does reflect directly electrical activity — not only where it is but how strong it is,” said Gore, the Hertha Ramsey Cress University Professor of Radiology and Radiological Sciences and professor of Biomedical Engineering. “It clarifies one of the uncertainties in the fMRI field.”
The researchers used high-field fMRI, in the range of 188,000 times the strength of the earth’s magnetic field.
They found that the technique can accurately map functional connectivity — synchronous fluctuations in the electrical frequencies of two parts of the brain that suggest they are working together — when the brain is at a resting state and when it is actively engaged.
“BOLD at high field provides a reliable tool for the investigation of cortical micro-organization,” said first author Zhaoyue Shi, a graduate student in Biomedical Engineering.
“This gives you a very powerful tool,” added co-author Li Min Chen, M.D., Ph.D., associate professor of Radiology and Radiological Sciences. It may prove useful in helping to improve the precision of neurosurgery as well as monitoring recovery from spinal cord injuries and brain injuries such as stroke, she said.
Other co-authors were Ruiqi Wu, Ph.D., Pai-Feng Yang, Ph.D., Feng Wang, Ph.D., Tung-Lin Wu and Arabinda Mishra. The research was supported by National Institutes of Health grants NS078680 and NS069909.
