Your brain on acid: A new way to image brain function

University of Iowa neuroscientist John Wemmie’s studies suggest that pH changes are important for normal brain activity and increased acidity is linked to anxiety and depression. However, while many pH measurement kits are available, none exist to measure pH in the brain. Wemmie teamed up with Vincent Magnotta, associate professor of radiology, psychiatry, and biomedical engineering, to develop and test a new method to monitor pH changes in living brains. Their MRI-based method was able to detect global changes in brain pH in mice. Breathing carbon dioxide, which lowers pH, increased the signal, while bicarbonate injections, which increases brain pH, decreased the MRI signal. This technique may also provide a new way to image the brain. Currently, fMRI measures brain activity by detecting oxygen levels in the blood. The UI team showed that their method responds to pH changes but not to changes in blood oxygenation.