Report from SNM: PET study linking brain chemistry, behavior becomes Image of the Year

Using PET with carbon-11-labeled monoamine oxidase A inhibitor clorgyline, researchers from the Brookhaven National Laboratory have found an association between MAO-A brain activity and violent behavior. Their study was selected as Image of the Year at the 2007 Society of Nuclear Medicine meeting in Washington, DC.

One of the most interesting topics in science today is the relationship between the mind and the brain. The SNM has provided the venue this year to showcase studies that discuss the coming together of mind and brain, said Dr. Henry N. Wagner Jr., a professor of environmental health sciences at Johns Hopkins University and past president of the SNM.

"The Image of the Year reflects the fact that the chemistry of the brain is now being extensively measured in human beings using radioactive tracer techniques," Wagner said.

C-11 PET shows evidence that violent, aggressive behavior could be associated with the activity of the brain enzyme monoamine oxidase A. (Provided by the Brookhaven National Laboratory)

He selected the image from more than 2000 studies, including scientific presentations and posters from the 2007 conference.

The winning image actually comprises four pictures: a view of a human gene with high and low concentrations of MAO-A, a PET scan showing brain MAO-A activity, and two photographs of humans displaying aggressive or violent behavior.

The study tries to explain how scientists are beginning to investigate the complex relationship between the biology of humans and their behavior toward others, said principal investigator Nelly Alia-Klein, Ph.D., an assistant scientist at the Brookhaven Center for Translational Neuroimaging in Upton, NY.

Alia-Klein and colleagues measured MAO-A activity in 38 healthy individuals identified as carriers of the high (n = 26) and low (n = 12) genotype variants of MAO-A. The subjects volunteered to answer a questionnaire while undergoing C-11 PET. The investigators found that subjects with higher scores on trait aggression had lower MAO-A brain activity. The correlation between both MAO-A genotype groups was similar and statistically significant (p < 0.05).

Study results suggest that an individual's genetic and brain makeup can influence aggressive behavior, even if that individual has no history of personality disorder. The study showed that subjects with more of the brain MAO-A enzymatic activity reported less aggressive behavior in a personality questionnaire, Alia-Klein said.

For more information from the Diagnostic Imaging archives:

3D MRI examines structural patterns of gray matter and bipolar disease

Functional MRI reveals clues to social behavior

Imaging genomics unveils roots of aggression