Chuck Bednar for redOrbit.com – @BednarChuck

A person’s degree of sensitivity to highly emotional information may depend to some degree on their genes, researchers from the University of British Columbia (UBC) report in a new study.

Writing in a recent edition of The Journal of Neuroscience, UBC psychology professor Rebecca Todd and her colleagues explained that carriers of a specific genetic variation tended to have more vivid, intense perceptions of both positive and negative images.

In addition, they found that those individual had heightened levels of activity in those regions of the brain responsible for regulating emotions and evaluating both pleasure and threat. According to Todd, this may explain why some people are more susceptible to PTSD.

“People really do see the world differently,” she explained in a statement. “For people with this gene variation, the emotionally relevant things in the world stand out much more.”

The culprit: a deletion variant of the gene ADRA2b

The variation in question occurs in the gene ADRA2b, which influences the neurotransmitter norepinephrine. Previously, Todd had discovered that carriers of a deletion variant of the gene paid more attention to negative words, and in her new study, she for the first time used brain imaging to examine how the gene affects people’s perception of the world.

“We thought, from our previous research, that people with the deletion variant would probably show this emotionally enhanced vividness,” the UBC psychologist explained. She and her team scanned the brains of 39 people, including 21 carriers of the ADRA2b variation, and found that they had far higher levels of what is known as emotionally enhanced vividness (EEV).

The study participants were asked to estimate the amount of pixelation or “noise” applied to images with positive, negative or neutral emotional content. Carriers of the genetic variant were more likely to estimate lower levels of noise on positive and negative images, relative to neutral images, than non-carriers. Furthermore, they had significantly more brain activity reflecting EEV in key regions of the brain sensitive to emotional relevance, the authors said.

Image shows increased activity in the brains of ADRA2b deletion carriers. (Credit: University of British Columbia)

“Emotions are not only about how feel about the world, but how our brains influence our perception of it,” said senior author Adam Anderson, professor of human development at Cornell University. “As our genes influence how we literally see the positive and negative aspects of our world more clearly, we may come to believe the world has more rewards or threats.”

Todd noted that carrying the gene variant can also be beneficial: “People who have the deletion variant are drawing on an additional network in their brains important for calculating the emotional relevance of things in the world. In any situation where noticing what’s relevant in the environment is important, this gene variation would be a positive.”

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