Deception: is there a neural activation pattern associated with truth inhibition?

  The Langleben et al. article "Brain Activity during Simulated Deception: An Event-Related Functional Magnetic Resonance Study" supports the existence of a link between deception and a corresponding neural activation pattern. Initially, researchers questioned the possibility of identifying a difference in neural activity when lying and telling the truth using fMRI brain imaging. They then questioned whether or not this activity would indicate truth inhibition in the prefrontal cortex and cingulate. These inquiries led to a laboratory adaptation of the Guilty Knowledge Test (GKT), involving twenty-three participants, each of whom received an envelope containing a $20 bill and a 5 of Clubs playing card. Each participant was told that he or she would be able to keep the $20 bill if able to successfully belie his or her card’s identity from a computer—the MRI scanner—that would ask the questions: “Do you have this card?” and “Is this the 10 of Spades?”. Here, the 10 of Spades operated as the Control card. The participants were encouraged to lie only about the identity of the 5 of Clubs, reducing anxiety-induced brain activity. Key results include neural-imaging evidence of truth inhibition as illustrated by elevated levels of right ACC activation when lying. This result follows a response inhibition archetype that deems the ACC as a monitor for conflicting responses, which means that right ACC activation indicates the site where the option to tell the truth was processed and then shut down in favor of lying. Furthermore, an increase in motor activation when lying about possessing the 5 of Clubs indicates a physical effort associated with truth inhibition, suggesting that truth is the natural cognitive inclination, and that one must first shut down this primary response before being able to lie.

 This increase in BOLD fMRI signal indicates that the difference between lying and telling the truth on the GKT can be detected and localized using BOLD fMRI. Also, although tentative, the lack of participant anxiety implies a disconnect between ACC activation and anxiety during deception, further proving the unreliability of the traditional polygraph. Ultimately, the results of this study evince the existence of a traceable neural activation pattern associated with deception.

Langeleben et al (2002). Brain Activity during Simulated Deception: An Event-Related Functional Magnetic Resonance Study. NeuroImage 15, 727–732 (2002).