Jewish World Review

Researchers use brain activity as marketing tool, obesity clue | (KRT) Love chocolate? Hate being snubbed? Turned on by sexy pictures? Turned off by an ugly face?

Scientists are making rapid strides in identifying where and how your brain handles such feelings, from the overwhelming flush of romantic love to the shivers a favorite piece of music sends down your spine.

Brain researchers are using technologies that measure blood flow, electromagnetic radiation and other events going on in your head when you experience strong emotions. They believe their work can help deal with problems such as obesity, drug addiction, sex crimes and mental disease.

Their effort has also inspired a new field of "behavioral finance" or "neuromarketing," which studies what happens in the heads of consumers, investors and gamblers as they decide whether and how much risk to take.

"Studies of the brain are teaching us how, why and when investors make decisions to buy and sell," said Dr. Richard Peterson, a psychiatrist and financial consultant in San Francisco.

Advertising agencies are beginning to use brain imaging to study what goes on in consumers' minds when they look at a product or an ad, Peterson said. The goal is to help create more effective commercials.

Justine Meaux, the research director of the BrightHouse Neurostrategies Group in Atlanta, described a neuromarketing experiment last week at the "Human Brain Mapping 2004" conference in Budapest.

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Magnetic brain scans of 13 volunteers showed that one area of their brains, the medial prefrontal cortex, lit up when they viewed images of fruits, cars, sports or hobbies that they especially liked, Meaux reported. Pictures of other objects didn't have the same effect.

Neuromarketing worries critics such as Gary Ruskin, the executive director of Commercial Alert, an organization founded by Ralph Nader that works to block advertising in schools and public areas.

"It is wrong to use a medical technology like brain scans for marketing," Ruskin said. More effective marketing of food or tobacco products could lead to more obesity or smoking, he cautioned.

Brain researchers' most powerful tools are Positron Emission Tomography (PET) and functional Magnetic Resonance Imaging (fMRI), two complementary technologies that reveal the living brain at work. Both are found in most hospitals and neurological laboratories.

In the PET system, a person lies in a scanner while a mild radioactive fluid traces the flow of blood through his or her brain. More blood flows to brain cells, or neurons, that are most active at the time. A radiation detector identifies the cells that are turned on when a person experiences emotions such as fear, hunger, pleasure or disgust.

An fMRI, in contrast, uses powerful magnets and radio waves to create pictures of the brain in action. The extra blood flowing to activated brain cells carries more oxygen, which alters the magnetic field in that area. Radio waves pin down the exact location of the magnetism. Color images - red for high intensity, yellow, green and blue for lower levels - identify which brain structures are busier than others.

An even newer technique is magnetoencephalography (MEG, for short), which identifies tiny magnetic fields generated by electrical activity in neurons. MEG can time events to thousandths of a second, far more precisely than fMRI. Researchers say knowing when things occur in the brain is as important as knowing where they happen.

Studies have shown that certain brain structures play relatively greater roles in one emotion compared with another. For example, the amygdala, a walnut-sized organ buried deep in the brain, is associated with fear. The caudate nucleus, a tail-shaped mass of brain cells linked to movement, lights up when a person feels disgust.

Researchers point out that these structures don't act in isolation. Rather, the brain cells in each area influence - and are influenced by - other regions through networks of complex circuits linking billions of neurons.

Antonio Tataranni, a nutrition expert at the National Institutes of Health's branch office in Phoenix, is trying to unravel the connections between human brain activity and obesity. He found that six different regions in the brains of 55 volunteers responded in different ways depending on whether the subjects were hungry or full, fat or thin.

Tataranni took PET scans of the volunteers after they had gone without food for 36 hours, and again after they were fed a hearty meal. He discovered significant changes in the way six different sites in the volunteers' brains responded to hunger and fullness.

"Different regions of the brain work in concert to orchestrate normal eating behaviors and conspire to produce obesity and other eating disorders," he said.

Of special interest were 11 formerly obese men and women. Tataranni said this group is "at high risk for relapse" because their brain scans resembled those of fat people more than thin ones.

"We are now working on the vastly more important and complicated questions of which of these neural differences may cause obesity in the first place," Tataranni said.

In another experiment, Dana Small, a neuroscientist at Northwestern University in Evanston, Ill., took PET scans of volunteers while feeding them pieces of chocolate. Five areas in their brains lit up while the participants were still hungry, but three different regions were activated when they had eaten too much.

Small concluded that the brain has separate motivational systems - one that's active when a person is hungry and the other for when he or she is full.

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© 2004, Distributed by Knight Ridder/Tribune Information Services