Scientists have long wondered why people with anxiety often seem paralyzed when it comes to decision-making. A new study reveals that people with anxiety have decreased neural inhibition in their brain, a process in which one nerve cell suppresses activity in another.
For the study, researchers wanted to test the theory that neural inhibition in the brain plays a big role in decision-making. So they developed a computer model of the brain called a “neural network simulation.”
“We found that if we increased the amount of inhibition in this simulated brain, our system got much better at making hard choices,” said Hannah Snyder, a psychology graduate student who worked with the researchers on the study.
“If we decreased inhibition in the brain, then the simulation had much more trouble making choices.”
Using the model, the team analyzed the brain mechanisms involved when we choose words. They then tested the model’s predictions on humans by asking them to think of the first verb that comes to mind when they are given a noun.
“We know that making decisions, in this case choosing our words, taps into this left-front region of the brain, called the left ventrolateral prefrontal cortex,” University of Colorado at Boulder psychology Professor Yuko Munakata, lead author of the study, said.
“We wanted to figure out what is happening in that part of the brain that lets us make these choices. Our idea here, which we have shown through the word-choosing model, is that there’s a fight between neurons in this area of the brain that lets us choose our words,” said Munakata.
They also tested the model’s predictions by observing the effects of increased and decreased inhibition in people’s brains.
Researchers increased inhibition with a drug called midazolam and found that people got much better at making hard decisions. It didn’t influence other aspects of their thinking, but only the area of making choices.
“We found that the worse their anxiety was, the worse they were at making decisions, and the activity in their left ventrolateral prefrontal cortex was less typical,” Munakata said.
The results of the study shed light on the brain mechanisms associated with making decisions and could be helpful in improving treatments for the millions of people who suffer from anxiety.
According to Snyder, there are drugs that already increase neural inhibition and these medications are currently being used to treat the emotional symptoms in anxiety disorders; however, the findings show that these drugs might also lessen the difficulty many sufferers of anxiety have in selecting one option when there are too many choices.
“[A] more precise understanding of what aspects of cognition patients are struggling with could be extremely valuable in designing effective approaches to therapy for each patient,” she said.
“For example, if someone with an anxiety disorder has difficulty selecting among multiple options, he or she might benefit from learning how to structure their environment to avoid choice overload.”
Said Munakata, “A lot of the pieces have been there. What’s new in this work is bringing all of this together to say here’s how we can fit all of these pieces of information together in a coherent framework explaining why it’s especially hard for people with anxiety to make decisions and why it links to neural inhibitors.”
A paper on the findings titled “Neural inhibition enables selection during language processing” was published in the Aug. 30 Proceedings of the National Academy of Sciences. CU-Boulder professors Tim Curran, Marie Banich and Randall O’Reilly, and graduate students Hannah Snyder and Erika Nyhus and undergraduate honors thesis student Natalie Hutchison co-authored the paper.