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New MRI technique can follow changes in brain pH. |
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EurekAlert: According to Wemmie, the new imaging technique provides the best evidence so far that pH changes do occur with normal function in the intact human brain. The findings were published May 7 in the Proceedings of the National Academy of Sciences (PNAS) Early Edition. Specifically, the study showed the MRI-based method was able to detect global changes in brain pH in mice. Breathing carbon dioxide, which lowers pH (makes the brain more acidic), increased the signal, while bicarbonate injections, which increases brain pH, decreased the MRI signal. The relationship between the signal and the pH was linear over the range that was tested. Importantly, the method also seems able to detect localized brain activity. When human volunteers viewed a flashing checkerboard -- a classic experiment that activates a particular brain region involved in vision -- the MRI method detected a drop in pH in that region. The team also confirmed the pH drop using other methods. "Our study tells us, first, we have a technique that we believe can measure pH changes in the brain, and second, this MRI-based technique suggests that pH changes do occur with brain function," Magnotta says.
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