volkow

In fact, for anything that links an action and a reward, "dopamine is indispensable for the formation of these habits, " Volkow says.

Dr. Nora Volkow, director of the National Institute on Drug Abuse, admits she, too, has a hard time resisting the call of her BlackBerry.

Dr. Volkow says she would not be concerned that fifty minutes of cell phone exposure would harm anyone.

Volkow and a team of researchers scanned the brains of 47 people with a cellphone attached to each side of their head.

A dopamine-rich part of the brain named the striatum memorizes routines that are linked to getting a particular reward, said Volkow.

"You see people immediately eating in the airport when their flight is canceled, " Volkow points out.

Still, Volkow said, understanding close-up and long-term exposure to cellphone radiation is important.

Dr. Volkow's work has been instrumental in demonstrating that drug addiction is a disease of the human brain.

For instance, glucose metabolism in the language centers of the brain rises by about 10 percent when a person is talking, Volkow says.

Dr. Volkow says the brain scans showed increased activity in brain cells closest to the activated phone.

The particular brain regions affected would probably change depending on a phone's design and how a person held it, Volkow says.

Volkow said, however, that most research has produced conflicting results.

Reward yourself with something you really desire, Volkow stresses.

"I don't like popcorn. But every time I go to the cinema, I have to eat it, " Volkow says. "It's fascinating. "