See a Lie Inside the Brain

Harvey Nathan is on a mission to prove he's not a liar.

"It's a gut-wrenching experience, " Nathan said. "It's bad."

In 2003, a deli he owned in Charleston, S.C., burned to the ground. Nathan's insurance company accused him of deliberately setting the fire to collect money on his insurance policy and pressed criminal charges.

A judge dismissed the case, but Nathan says his insurance company still does not believe him and has yet to pay for the damage.

"It's frustrating to go through and know there's nothing you can do," Nathan said.

So Nathan went to a new company based in San Diego called No Lie MRI, which claims to use "the first and only direct detection of lies in human history" by actually mapping the portion of the brain that's used in deception.

Polygraph tests, the old standard of being able to tell when someone is lying, are rarely admitted as evidence into court. The polygraph measures blood pressure, sweat and breathing, among other things, to look for emotional signs of lying. But it is possible in some cases for people to learn to control these things and trick the machine.

Now there may be a solution: a truth serum without the needles.

"Whether it's the spouse that hasn't been cheating, but his partner thinks he was, or the person that didn't take the money," said the founder of No Lie MRI, Joel Huizenga, "this is all about people being vindicated when they've been wrongly accused."

Find the Lie — Follow the Blood in the Brain

The technology his company uses is called functional magnetic resonance imaging, or FMRI.

Here's how it works: When someone lies, the brain first stops itself from telling the truth, then generates the deception. When the brain is working hard at lying, more blood rushes to specific portions of the brain and that's what can be detected on the machine.

While No Lie MRI is already offering the service to select customers, a company based in Massachusetts called Cephos, founded by Steven Laken, is taking a more cautious approach with the technology.

Laken's company is still researching the FMRI at the Medical University of South Carolina to look for more positive results before it brings the service to the market.

"What we have now is a controlled lab experiment, where people commit a crime and try to lie to us and see if we can use imaging results to see what they were lying about," said Mark George, who is running the studies commissioned by Cephos at the Medical University of South Carolina. "Through these studies, we've been pretty good — 90 [percent] to 95 percent accuracy rate so far."

Put the Test to the Test

The researchers testing the technology agreed to let ABC News try it out.

Our experiment started with a mock crime. I was told to either steal a ring or a watch from a drawer in the lab and then go under the FMRI machine and lie about what I had taken.

The FMRI results visibly showed more blood rushing to the specific parts of the brain when I was lying.

"We're looking beyond just the anxiety, what you're doing cognitively when telling a lie. When you're telling a lie, you're overriding a normal response of telling the truth, " said George. "So your brain is putting on a brake and overlearning a response. It's harder to tell a lie then tell the truth, [to] remember what you're lying about. You've created a false way the world is. So we're looking at overworking, inhibiting, multitasking. Those areas are pretty predictive in catching someone when you're lying."

The FMRI technology is still not admissible in court, but there's potentially a huge market for use in situations like libel, slander and fraud where it's one person's word against another, and in employee screening by government agencies.

A law review article has discussed the legality of using FMRI to interrogate foreigners in U.S. custody.

"If the science results continue to be good, you could use in courts of law people saying, 'I did this, didn't do that,'" George said. "Also, [it could be used] for security clearances to figure out if someone is a member of a different group. Security clearance and courts of law are biggest areas for potential use."

As for the deli owner Harvey Nathan, he says No Lie MRI gave him a chance to clear his name, giving him proof that he is innocent — even though his insurance company has not chosen to accept the FMRI results yet.