Atlanta ? Some people have chocolate on the brain.

A new study of people who crave chocolate shows that eating chocolate, or even just looking at a picture of it, turns on pleasure centers in the brains of cravers far more than in people who don’t crave the confection. Viewing pictures of chocolate also activates an area of the brain known to be involved in drug addiction.

The study, by Ciara McCabe and Edmund T. Rolls of Oxford University in England, was one of more than 14,000 presentations slated for the annual meeting of the Society for Neuroscience this week in Atlanta.

McCabe gathered seven chocolate cravers and eight noncravers for her experiment. All of the subjects completed a survey to confirm their chocolate craving status. The differences were clear. Some people really don’t crave chocolate, a fact McCabe – an admitted chocolate craver – finds incredible.

She placed the volunteers in a functional magnetic-resonance imaging machine – a scanner that measures activity in the brain. Once the people were in the scanner, McCabe gave them a taste of liquid chocolate.

A stack of different varities of chocolate chunks.

The cravers and noncravers registered the taste to the same degree in parts of the brain involved in detecting taste. But people who crave chocolate perceived the taste as more pleasant than did the noncravers. The difference showed up in the brain scan and in the volunteers’ ratings of the experience.

When McCabe showed mouth-watering pictures of chocolate to cravers, the ventral striatum, a part of the brain involved in drug addiction, turned on. Noncravers showed no activity in that part of the brain.

The researchers don’t yet know why some people crave chocolate while others don’t. The answer could help scientists understand people’s food preferences and eating patterns.