MIT Unlocks Mystery Behind Brain Imaging Star-Shaped Brain Cells Shown To Play Key Role

19 Jun 2008
http://www.medicalnewstoday.com/articles/111590.php

In work that solves a long-standing mystery in neuroscience, researchers at MIT's Picower Institute for Learning and Memory have shown for the first time that star-shaped brain cells called astrocytes-previously considered bit players by most neuroscientists-make noninvasive brain scans possible.

Imaging techniques such as functional magnetic resonance imaging (fMRI) and positron emission tomography (PET) have transformed neuroscience, providing colorful maps of brain activity in living subjects. The scans' reds, oranges, yellows and blues represent changes in blood flow and volume triggered by neural activity. But until the MIT study, reported in the June 20 issue of Science, no one knew exactly why this worked.

"Why blood flow is linked to neuronal activity has been a mystery," said study co-author Mriganka Sur, Sherman Fairchild Professor of Neuroscience and head of the Department of Brain and Cognitive Sciences at MIT. "Previously, people have argued that the fMRI signal reports local field potentials or waves of incoming electrical activity, but neurons do not connect directly to blood vessels. A causal link between neuronal activity and blood flow has never been shown."

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