Your brain may give you away when you're telling a lie, a new study suggests. Research presented on Tuesday at the national meeting of the Society for Neuroscience revealed differences in brain activity when people told the truth versus when they fibbed.

Daniel Langleben and colleagues at the University of Pennsylvania used functional magnetic resonance imaging (fMRI) to study the brains of volunteers taking what is known as the Guilty Knowledge Test. In the test, participants were each given a playing cardthe five of clubs in this caseand were told to hide it in their pockets and deny holding it when asked. Later, in the MRI scanner, a computer flashed pictures of playing cards and asked the subjects if they had the card featured on the screen. "Sections of the brain that exercise a significant role in how humans pay attention, and monitor and control errors (the anterior cingulate gyrus and parts of the prefrontal and premotor cortex), were, on average, more active in the volunteers when they were lying than when they were telling the truth," Langleben reports.

The researchers suggest that there is a localized brain reaction that correlates to deception. In fact, according to Langleben, because fMRI provides a more direct measure of brain activity than does the polygraph, it may hold advantages over that approach to lie detection.