Steve Silberman at Wired has filed a detailed article on developments in fMRI research on identifying brain activity associated with deception in Issue 14.01 – January 2006.
[…] fMRI is poised to transform the security industry, the judicial system, and our fundamental notions of privacy. I’m in a lab at Columbia University, where scientists are using the technology to analyze the cognitive differences between truth and lies. By mapping the neural circuits behind deception, researchers are turning fMRI into a new kind of lie detector that’s more probing and accurate than the polygraph, the standard lie-detection tool employed by law enforcement and intelligence agencies for nearly a century.
Silberman has done a thorough job, but glosses over many of the theoretical and practical problems with application of this technique in law enforcement work, including the fact that it requires a highly co-operative subject – and one without any metal of any kind, including shrapnel (which might impact on its usefulness in military interrogation scenarios?) in their body, given that the test involves lying in a giant magnet. There are also potential legal and ethical issues – see:
Cory Doctorow’s comment at Boing Boing
Thompson, Sean Kevin, The Legality of the Use of Psychiatric Neuroimaging in Intelligence Interrogation. Cornell Law Review, Vol. 90, No. 6, September 2005. (The link is to the abstract, from where you can currently access the full text pdf).
Slate Magazine’s comment on Technology vs torture, 18 Aug 2004 also discusses the legal and ethical issues surrounding the use of fMRI and similar technologies during interrogation.