Neuroscience for Kids

Moody Brains

By Melissa Lee Phillips
Neuroscience for Kids Consultant
March 8, 2002
A group of scientists has identified an area of the brain that seems to be associated with negative moods. The researchers, led by David H. Zald, Ph.D. of Vanderbilt University, found that people who tend to experience high levels of anxiety, irritability, anger and other unpleasant moods are more likely to have a high level of activity in the ventromedial prefrontal cortex (VMPFC).
Individuals differ in the range of negative moods and emotions that they experience. Over time, some people experience negative mood states more consistently and more severely than others. The purpose of Zald's study was to identify a relationship between negative moods and activity in a specific area of the brain.
Study participants were given a questionnaire that asked them to rate their negative emotions during the previous month. Researchers then measured the resting blood flow in each person's brain using the brain imaging technique called positron emission tomography (PET).
When the scores from the questionnaire were compared with the PET scan images, the researchers found that people who reported experiencing frequent negative emotions over the past month usually had higher levels of activity in the VMPFC. The scientists also looked for a correlation between activity in the VMPFC and positive emotional states, but they found none. Activity in this brain area seems to be linked only to the negative aspects of mood.
These results agree with data from other studies that have implicated the VMPFC in emotional processing. For example, patients with damage to the VMPFC lack emotional responses to various situations. Also, the VMPFC has been linked with emotional disturbances in people with certain psychiatric conditions.
Zald and his colleagues emphasize that although the study suggests a correlation between chronic negative moods and activity in the VMPFC, it is not known what causes the changes. It may be that people experience negative mood states because they have high activity in the VMPFC, or it could be possible that negative moods cause increased activity in the VMPFC. Other factors not measured in the study may also be the actual cause of the observed results. A correlation means that two variables are related, but it does not provide any information about what causes the relationship.

Reference:

Zald, D.H., Mattson, D.L., and Pardo, J.V., "Brain activity in ventromedial prefrontal cortex correlates with individual differences in negative affect," Proc. Natl. Acad. Sci. USA, Vol. 99, Issue 4, February 19, 2002, pp. 2450-2454.

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