A UW study that used functional magnetic resonance imaging to observe brain responses to aversive pictures in subjects showed what most college students already know: uncertainty about life events is scary.
Subjects in the study were presented with a mix of aversive and neutral pictures. Pictures were also preceded by a circle to indicate an upcoming neutral picture, an X to indicate an upcoming aversive picture, and a question mark when either a neutral or aversive picture could be presented.
Researchers showed subjects adversive pictures both with and without warning to record which brain regions responded to the stimuli.
“In terms of stress, each group has different stressors,” Bob McGrath, director of UW Counseling and Consultation Services, said. “For freshmen, it’s adjustment to this incredibly new experience For juniors and seniors, it might not be stress but uncertainty about what comes next in life.”
“What we’ve shown in this study is that thinking something bad might happen actually leads to a larger brain response in the key areas that are involved in emotion—the amygdala and the insula,” Jack Nitschke, a UW professor of psychiatry and co-author on the study, said.
The brain scans showed that the amygdala and insula regions of subjects’ brains responded more strongly to the appearance of the question mark when the nature of the forthcoming picture was uncertain. This activation of the amygdala and insula is also associated with the activation of another brain region key to the regulation of emotions—the anterior cingulate cortex (ACC).
“The ACC is involved in telling other brain areas: you know, we do or don’t need you so much,” Nitschke explained.
Essentially, the ACC passes a message to the amygdala and the insula to either increase or decrease activation because, depending on whether something unexpected versus something expected is coming up.
The study showed that there were individuals that showed a big difference in their insula and amygdala response to the aversive pictures, depending on whether it was preceded by an X or a question mark. These were also the individuals whose ACC region responded similarly, with little difference, when presented with either the X or question mark.
“So there is an association—essentially that the ACC is predicting how much the insula and the amygdala activation is going to differ between the X and the question mark,” said Nitschke.
Following the brain scan, subjects were also asked to report how often an aversive picture followed a question mark. Although question marks were followed by aversive pictures exactly 50 percent of the time, 75 percent of subjects reported that question marks were more often followed by aversive pictures. None of the subjects reported that neutral pictures were more common than they actually were.
“In other words, people are biased in their retrospective accounts—in their memory of what they just experienced,” Nitschke said.
The fMRI data shows that activation of the ACC, insula and amygdala corresponds to the biased estimates following the scan.
According to Nitschke, it seems that, in uncertain situations, the brain is prepared for the worst.
“[The brain] is anticipating the future, specifically when there is uncertainty, and that is the key to anxiety,” Nitschke said. “That’s what we’re trying to take apart.”
Nitschke said that the brains of healthy subjects showed that the brain was being adaptive in responding to uncertainty in certain ways. When people are presented with uncertainty, they show an amplified brain response in key emotion centers.
“Next, we could like to study what happens in the case of people who are actually suffering from anxiety disorders—when uncertain anticipation is a very real part of their everyday life,” Nitschke said.
The more that is known about the interplay of uncertainty and anxiety, the more hope there is for treatment.
“We can potentially start to target these brain regions through different types of treatment modalities,” Nitschke said.
What you don't know can hurt you
Published: Monday, October 5, 2009
Updated: Tuesday, October 6, 2009
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