PET: A Scan for Brain Activity and a Case for Using It

There are a great many different methods for studying the brain. One method, the PET, is of particular interest, especially in the world of biopsychological research. You've probably heard of cases in which particular sections of the brain being responsible for certain behaviors. For example, Manchester University conducted a study on the brains of dancers verses non-dancers. The yielded visuals of activity in the visual cortex areas of the brain. Additionally, they found that the dancer's brain (the pre-motor cortex and the visual-motor integration cortex) showed significant activity in these areas when watching another dancer do movement that the testing dancer knew how to do. This came in contrast to no activity change in non-dancers. According to Manchester University's neuro lab (2008), "This shows that the dancers combine what they saw with their own personal 'motor repertoire'- and this shows up differently in their brain scans. It also shows that by lying still and simply watching other people move, you can activate movement areas of the brain as if you were moving yourself" (2008). Needless to say, brain scans such as the PET give researchers a look into the brain's role in behavior.

PET, or Positron Emission Tomography, provides images of activity within the brain, while other scans often show structure. More specifically, PET scans display a colored map which exhibits different colors based on the amount of radioactivity in each "cubic voxel (volume pixel)" (Pinel, 2006). This is limiting for doctors because they must knowledge of this measurement to estimate the activity regions and corresponding activity.

Color codes are given to the map on the PET, where red and yellow indicate high radioactivity. However, this contrast doesn't display alone on the PET or the brain. Instead, like other scans using a form of contrast, the PET relies on radioactive 2-deoxyglucose. This fluid is injected into the carotid artery (Pinel, 2006). Once the liquid is in the body, the patient participates in the action or behavior being studied. During the course of the action (around 30 seconds) scans are taken of the brain and its activity.

Today, the PET scan is used for both medical and research purposes. Researchers interested in the brain's role in behavior and thought or ideals have begun to study such controversial issues as the role of the brain in violence and hate. However, even if a connection were found between brain activity and violence. MRI scans are also being used for structural studies on these topics. Unfortunately, if a connection is found between the two if could be a double edged sword. While we will gain extremely valuable information, it may also be used as a scapegoat for poor behavior. Only time will tell what course these studies ultimately go, and what use they will be in the criminal justice and legal systems. Still, benefits from scans the PET can help us to understand learning, better ways to communicate information, and the difference between individual's behaviors.

References:

Manchester University. (2008). The Dancers Brain. Retrieved February 13, 2008, from: http://www.youramazingbrain.org.uk/Brainbody/dancers.htm

Pinel, J. P.J. (2006). Biopsychology, 6^th Edition. University of British Columbia. Pearson.