Advanced Imaging


Advanced Imaging Magazine

Updated: January 12th, 2011 10:01 AM CDT

The Inside Image

Truth or lie? Brain imaging may become the ultimate test
functional magnetic resonance imaging (fMRI)
© University of Wisconsin (Madison) Laboratory for Affective Neuroscience
The discovery of functional magnetic resonance imaging (fMRI) opened the door to picturing the dynamics of cognition.
© University of Wisconsin (Madison) Laboratory for Affective Neuroscience
fMRI shows great promise—and is receiving the most journalistic exposure—for brain mapping; understanding the physical events which beget human sensation, attention and awareness.

By Lee J. Nelson
Contributing Editor

In the aftermath of Sept. 11, 2001, the Federal Government persuaded Americans to surrender a large measure of our right to privacy in exchange for the promise of heightened national security. Examples are omnipresent. They run the gamut from provisions contained in The USA Patriot Improvement and Reauthorization Act of 2005 and The Reauthorizing Amendments Act of 2006, to domestic spying, airport frisking and—in some cases—the presumption of guilt. Technology is being exploited to analyze what we say, what we do, how we look and where we travel. Now, that last bastion of privacy, what we think, may be at risk.

For decades, the polygraph machine has been the de facto standard for peering inside a subject's mind. But, as it is increasingly controversial (ie: divisive validity, legal inadmissibility), sparking a cottage industry to "beat" the test, authorities are hunting for newer ways to solve that time-honored dilemma: how to tell if someone is lying?

The advent of non-invasive imaging, of course, let us see inside the head. In the early 1990s, scientists at the Medical College of Wisconsin's Biophysics Research Institute (Milwaukee) demonstrated that magnetic resonance imaging could visualize changes in the living brain. Their discovery—simultaneously with Massachusetts General Hospital/Harvard University (Boston) and the University of Minnesota (Minneapolis)—of functional magnetic resonance imaging (fMRI) opened the door to picturing the dynamics of cognition. Today, various complementary modalities are advancing our ability to view the brain at work. Beyond beneficial medical applications, imaging and interpreting thoughts poses a host of potential new Orwellian implications.

According to Prof. Ruben Gur, Director of the Brain-Behavior Laboratory at the University of Pennsylvania School of Medicine (Philadelphia), functional brain imaging substantiates that "...truth is always simpler. To make a lie, you have to know what is true and you have to distort it. That is extra work that goes into lying."

Localized increases in blood-flow often accompany such neural activity. That causes a corresponding reduction in deoxyhemoglobin because heightened perfusion occurs without a concomitant rise in oxygen extraction. Thus, deoxyhemoglobin—sometimes referred to as an endogenous contrast enhancing agent—serves as the indicator for fMRI. From an appropriate imaging sequence, human cortical processes can be seen directly: more oxygenated blood in a particular region correlates with greater activity, allowing researchers to associate those observations with the subject's distinct thoughts and behaviors.

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