Essentially, it's about monitoring how fresh blood flows into part of the brain when Britney Spears gyrates in a soft-drink ad.

Functional Magnetic Resonance Imaging, or fMRI, is the latest craze in high-end advertising, and it's starting to seduce corporations that market their wares to Czechs. The technology allows media buyers to engage in what they call neuroplanning — and there are good reasons why it's a hot item.

Creating an advertising blitz based on brain research has a wonderfully Dr. Strangelove appeal (some would say Orwellian); it's very expensive (clients like Unilever and DaimlerChrysler have so far bought into studies that can easily cost from $94,000 (2.1 million Kč) to $188,000 for a "medium-size" session); and it's mysterious (thus, clients can never prove they didn't get their money's worth).

All this thanks to medical breakthroughs developed to help doctors understand cerebral injuries and processes in a noninvasive way. fMRI employs powerful magnetic waves to monitor when blood with differently charged oxygen enters the brain and where it goes, which is a tag indicating that part of the brain is in use.

One of the key studies that made the advertising world sit up and notice fMRI's potential was conducted at Baylor College of Medicine in 2004. That research showed that a blind taste test between Coke and Pepsi resulted in no clear preference, but, when each product was clearly labeled, brain activity in the amygdala of Coke-drinking subjects lit right up. Conclusion: Because this part of the brain is a center for emotions, test volunteers seemed to have warm feelings for one brand over the other.

Does this mean that they are any more likely to buy Coca-Cola? Well, now, that's a question that's going to require much further study using still more amazing technology — which has, alas, not been developed yet.

No matter. If Unilever and DaimlerChrysler are shelling out to put test consumers into a pod at a high-tech medical center, any serious global marketing maven had better do the same.

Which means that, apart from a few awkward ethical arguments like the ones made by Cognitive Liberty (www.cognitiveliberty.org) and Ralph Nader's Commercial Alert (commercialalert.org), which suggest scenes of balding men in lab coats gleefully hunting down your brain's "buy button" to send you into a shopping trance, this could be good news for universities.

Because of the cost, even the big-time ad agencies don't own their own MRI machines and are thus compelled to rent lab time from local medical schools. If the popularity of probing the neurological responses to various ads and types of media continues to grow, such schools will be able to name their price for access to the machines. Meanwhile, those with expertise in interpreting the results will find some serious moonlighting income in lending their opinions to marketing folk.

There's always a better mousetrap, of course, and scientists at Cambridge University and the Massachusetts Institute of Technology believe that consumers' emotional responses to Web page ads can be measured just as effectively and far more economically with software and video cameras that are able to pick up the slightest movement patterns in 24 areas of the face.

Something to consider when buying the PC of the future with this sofware pre-installed and a free Web cam. Until that time, the ethics of commercial applications for science originally developed for medicine is a no brainer. As long as genuinely beneficial research with magnetic imaging continues, why shouldn't universities be able to reap a return on this expensive technology?