T1rho Imaging to Assess Brain Ph Dynamics

Vincent A. Magnotta, Ph.D.

University of Iowa College of Medicine

Grant Program:

David Mahoney Neuroimaging Program

Funded in:

June 2010, for 3 years

Funding Amount:

$200,000

Lay Summary

Imaging patients with panic disorder may reveal the role that low brain acid levels may play

In this study, investigators will use magnetic resonance spectroscopy (MRS) imaging to explore whether panic disorder could result from abnormally low levels of acidity (pH) in the brain.

The brain maintains a balance between acidity and alkalinity (which neutralizes acid). Neural activity and neurological diseases have been shown to produce fluctuations in the levels of brain acidity. The investigators’ prior research has shown that fluctuation in acidity levels activates receptors for protons (positively charged particles) but the receptor’s role in brain signaling processes is just beginning to be understood. Evidence shows that proton receptors contribute to behavior, and receptor abnormalities have been implicated in psychiatric diseases such as anxiety and depression. Moreover, animal studies indicate that behavior produces transient low acidity levels. This finding has led the researchers to hypothesize that: 1) neural activity reduces acid levels in the human brain; and 2) Neural activity will significantly lower acid levels in people with panic disorder compared to healthy volunteers.

They will test this hypothesis in 20 patients suffering from panic disorder and 20 healthy volunteers using an MRI imaging technique they developed that is sensitive to changes in acid levels in the human brain. They will image the participants before and after they are presented with a flashing checkerboard to stimulate neuronal activity. If the patients show lower acidity levels in response to the stimulation, compared to controls, this technique could serve as a biomarker for panic disorder.

Significance: This new imaging technique could serve as a biomarker for panic disorder, providing a way to biologically assess the effects of experimental therapies. It also may lead to identification of disease pathways and creation of new therapeutic interventions that affect those pathways.