Fall 1995 Volume 4, Number 4

Investigating the Biology of Human Drug Addiction

Many people are so hooked on cocaine or other drugs that they continue to use the substances, even when social, economic or health consequences are devastating. Research in laboratory animals is providing an understanding of the important brain structures involved in the development and maintenance of drug dependence, but whether the same brain structures are responsible for drug abuse in humans is an open question.

At Massachusetts General Hospital and Harvard Medical School, investigator Josh Berke reports, a team led by Steven Hyman is using functional magnetic resonance imaging (fMRI) to observe the brains of crack users while they are injected with cocaine. (These are all longtime cocaine users who have agreed to enter treatment at the conclusion of the study and are retained at the hospital until the effects of the injection wears off.)

Regional changes accompany neuronal activity in specialized parts of the brain, and fMRI shows these changes by providing rapid, high quality pictures of blood flow and oxygen use. The challenge confronting the team is to relate dynamic changes in regional brain activity to subjective responses measured at the same time.

In addition, they are studying the brains of crack users while these patients are craving cocaine. This should lead to a greater understanding of the psychobiological processes that cause compulsive use and also relapse.

MRI changes due to cocaine injection, caused by cocaine's direct effects on blood vessels in the brain and neuronal activity. Reading from top, left to right, images begin with the top of the skull and progress downward to the base of the skull. Blue areas indicate the mildest effect and yellow the most intense. (Courtesy of Mr. Berke.)

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