Scientists measure brain function

Posted on Monday, February 13th, 2012

Despite advances in neuroscience, much about how the brain functions remains a mystery. To figure out what is going on inside your head, doctors rely on a combination of indirect indicators, such as changes in blood flow or electrical activity of the brain. A new clinical study challenges a widely held belief about the relationship between these two measures of brain function.

“This is a step toward further understanding how the brain operates so surgeries can be even more precise,” says Nitin Tandon, M.D., the study’s senior author and UT Physicians neurosurgeon.

Findings by Dr. Tandon and his neurosurgeon appear in a recent issue of The Journal of Neuroscience, the official journal of the Society for Neuroscience.

Doctors use these indicators to identify areas of the brain tied to diseases like epilepsy, a disorder that affects about 50 million worldwide and can cause seizures. One treatment option involves the surgical removal of the diseased area of the brain.

When your brain kicks into gear, its nerve cells, or neurons, emit tiny electrical charges and trigger the circulation of oxygen-rich blood. For years, it has been thought that the relationship between brain activity and the changes in blood flow was a fixed one.

To test this relationship closely, Dr. Tandon, a member of the Mischer Neuroscience Institute at Memorial Hermann, conducted a study involving 11 people with epilepsy who needed to have electrodes placed on the brain surface to pinpoint the origin of seizures precisely.

These patients were asked to answer questions about images on a computer screen. During the first battery of questions, the intracranial blood flow of participants was observed with the aid of magnetic resonance imaging. During the second round of questions, the intracranial electrical activity was monitored with electrodes attached to the brain.

Dr. Tandon’s team found changes in the relationship between these two indicators based on the location of the electrodes.

The study titled “Variability of the Relationship between Electrophysiology and BOLD-fMRI across Cortical Regions in Humans” received support from the Center for Clinical and Translational Sciences at UTHealth, the National Institutes of Health, and the Vivian L. Smith Foundation for Neurologic Research.

— Robert Cahill, Office of Advancement, Media Relations

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