Rat Study Shows Anxiety Can Lead to Bad Decisions

New research suggests a mechanism for how anxiety may disrupt decision-making.

In a study published in The Journal of Neuroscience, scientists at the University of Pittsburgh report that anxiety disengages the prefrontal cortex (PFC).

The PFC is an important brain region as it is critical for flexible decision-making. By monitoring the activity of neurons in the PFC while anxious rats had to make decisions about how to get a reward, the scientists made two observations.

First, anxiety leads to bad decisions when there are conflicting distractors present. Second, bad decisions under anxiety involve numbing of PFC neurons.

Research findings indicate that anxiety has an exquisitely selective effect on neuronal activity that supports decision-making, said Bita Moghaddam, Ph.D., lead author of the study.

Up to now, scientists have mostly studied anxiety in animal models in the context of fear and measured how brain cells react to a threatening situation.

But human anxiety is devastating, not merely because of how the person feels, but also because it can interfere with nearly all aspects of daily life including decision-making, said Moghaddam.

Investigators studied this aspect of anxiety by monitoring the activity of a large number of neurons as rats made decisions about which choice was most optimal for receiving a reward. They compared behavior and neuronal activity in two groups: one group that had a placebo injection and another that got a low dose of an anxiety-inducing drug.

As with many people who suffer from anxiety but go through day-to-day life and make decisions, the anxious rats completed the decision-making task and, actually, did not do too badly.

However, they made far more mistakes when the correct choice involved ignoring distracting information.

“A brain locus of vulnerability for these anxiety-induced mistakes was a group of cells in the PFC that specifically coded for choice. Anxiety weakened the coding power of these neurons, Moghaddam said.

“We have had a simplistic approach to studying and treating anxiety. We have equated it with fear and have mostly assumed that it over-engages entire brain circuits. But this study shows that anxiety disengages brain cells in a highly specialized manner.”

Researchers believe future studies will improve our understanding of the brain mechanics behind anxiety and decision making. Moghaddam believes this could lead to better treatment of anxiety in people and, subsequently, better outcomes in the treatment of psychiatric disorders.

Source: University of Pittsburg