How Does Anxiety Short Circuit the Decision-Making Process?
Anxiety disengages neurons in the prefrontal cortex linked to decision-making.
Posted Mar 17, 2016
Neuroscientists at the University of Pittsburgh have pinpointed a specific neuronal mechanism that helps explain how anxiety can disrupt the decision-making process and often leads to poor choices. Decision-making is the cognitive process of making a choice between a number of possible alternatives that often involves weighing the risks, rewards, and consequences of your actions.
There is growing evidence that the cognitive process of decision-making depends on proper functioning of specific neurons within subregions of the prefrontal cortex (PFC). The prefrontal cortex—which is housed in the frontal lobes of the cerebrum—is the newest part of the human brain in terms of our evolution.
The PFC plays a pivotal role in executive functions that include: long-term planning, understanding rules, calculating the consequences of risk and reward, regulating emotions, problem-solving, and decision-making. Anxiety, in both animals and humans, appears to disrupt brain neurons in the PFC that are critical for making smart decisions.
The Pitt researchers were curious to identify exactly how anxiety impacts the PFC during the decision-making process. In order to pinpoint which neurons were directly affected by anxiety, the researchers studied two groups of rats as they completed a decision-making task in which they had to decide the most logical choice for receiving a reward.
One reason the researchers of this study were motivated to pinpoint the neurobiological impact of distress on decision-making is because anxiety is such a prominent and debilitating component of most psychiatric disorders. Anxiety is often a key player in major depressive disorder (MDD), post-traumatic stress disorder (PTSD), schizophrenia, obsessive-compulsive disorders (OCD), and addiction.
For example, in addictive disorders, the researchers point out that addiction creates a vicious cycle that involves the inability to make good decisions that is fueled by the double whammy of substance abuse and anxiety. Based on their hypothesis, the anxiety associated with drug dependency (in and of itself) often leads to poor decision-making by disengaging neurons in the PFC, which then makes it harder to 'do the right thing' and stay clean.
The Pitt researchers are on a mission to learn more about how anxiety modulates PFC neuronal encoding during the decision-making process in order to improve the odds and outcomes of everyday choices people from all walks of life make in their daily lives.
Anxiety Disrupts the Decision-Making Regions of the Prefrontal Cortex (PFC)
Previous brain imaging studies on human behavior and anxiety have helped to decode the complex impact that anxiety has on PFC-related cognitive functions—including deficits in emotional regulation, cognitive flexibility, and the control of behavior.
For this study, the Pitt researchers monitored the activity of a large number of PFC neurons as anxiety-ridden rats made decisions about which choice was best for receiving a reward. They did the same with a group of rats that weren't stressed out. Although this was a study on rodents, the model of anxiety used in this experiment has also been validated in humans and monkeys.
The March 2016 study, "Anxiety Evokes Hypofrontality and Disrupts Rule-Relevant Encoding by Dorsomedial Prefrontal Cortex Neurons," was published in The Journal of Neuroscience. The study found that anxiety suppresses the general spontaneous activity of PFC neurons, as well as specifically weakening the encoding of task rules by dorsomedial PFC neurons. This subgroup of neurons is specifically coded for making a choice based on relevant rules.
By monitoring the activity of neurons in the PFC while anxious rats were problem-solving and making decisions in order to get a reward, the scientists made two important observations. First, anxiety often leads to bad decision-making, especially when there were conflicts or distractions. Second, bad decisions made under distress were correlated with the "unclamping" of very specific PFC neurons.
In a press release, Bita Moghaddam, the lead author of the study and a professor in the Department of Neuroscience and Psychiatry at University of Pittsburgh said,
"The data indicates that anxiety has an exquisitely selective effect on neuronal activity that supports decision making. 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."
Interestingly, the researchers found that the orbitofrontal cortex (OFC) brain region, which plays a role in problem-solving and learns through trial and error wasn’t affected by anxiety in this study. However, the Pitt researchers state in their conclusion, "It should be underscored that these findings do not discount a role for OFC in mediating other adverse effects of anxiety."
The new findings from Pitt dovetail seamlessly with another study on rule learning, decision-making, and the importance of active learning published last week by neuroscientists at the University of California, Berkeley. I wrote about this study in a recent Psychology Today blog post, “How Does the Brain Learn Through Trial and Error?”
The March 2016 UC Berkeley study, “Rule Learning Enhances Structural Plasticity of Long Range Axons in Frontal Cortex,” was published in the journal Nature Communications.
Using advanced microscopy techniques, the Berkeley researchers captured brain images of active learning in real-time by photographing the brains of mice as they learned how to problem-solve through trial and error. The films show dramatic resculpting in the OFC subregion within the prefrontal cortex during the problem-solving process of active learning.
The Teenage Prefrontal Cortex Is Especially Vulnerable to Anxiety
During early- and mid-adolescence, the brain undergoes considerable neural growth and pruning which create changes of connectivity within and between various brain regions including the PFC. As we all know, the transition from childhood to adolescence is riddled with a wide range of minefields and booby traps for most teenagers, especially when someone is prone to anxiety or under a lot of stress.
By some estimates, human brain development and connectivity isn’t fully complete until the age of 25. Some researchers have pointed out, that "rental car companies have it right" when it comes to decision-making and the prefrontal cortex. Ironically, the decision-making PFC isn't fully mature at 16, when a teenager can get a driver’s license; or at 18, when Americans are allowed to vote; or at 21, when we are allowed to drink, but closer to 25, when we are allowed to rent a car.
Healthy brain development requires a combination of brain plasticity, which fortifies certain connections so signals can be transmitted more efficiently ... and synaptic pruning, which causes other connections to atrophy. Many studies have shown that chronic anxiety and high levels of the "stress hormone" cortisol disrupt brain structure and functional connectivity of the PFC.
Teenage brain structure, neuronal connectivity, impulsive behavior, and decision-making are all intertwined. While modern-day teenagers are advancing to new levels of sophisticated thinking and technological savvy, they are also under increasing amounts of stress. Although the new Pitt study doesn't look at teenagers in particular, it would seem that the impact of high anxiety on the PFC would make it evermore difficult for anxious teenagers to make wise decisions.
The latest research suggests that helping teens manage anxiety is key to engaging the dorsomedial PFC neurons which leads to making better decisions. This could include the decision not to abuse drugs, start smoking, and, on the flip side, to make healthy lifestyle choices regarding diet and exercise. Teaching teenagers drug-free methods for reducing anxiety—combined with creating less stressful school environments—should be a top priority for parents, educators, and policymakers.
Conclusion: Reducing Anxiety Is Central to Improving Decision-Making
Hopefully, this research will inspire people of all ages to make the decision to be more proactive about reducing anxiety in an attempt to improve the structure and executive function of your prefrontal cortex. Anything you can do to reduce your anxiety will improve your ability to make better life choices at a neural level and create an upward spiral.
Reducing anxiety is especially important during chaotic times, when you feel overwhelmed, or that your life is out of control. During times of distress, the latest research shows that people are likely to make poor decisions which can exacerbate anxiety, lead to more bad decisions and snowball into a downward spiral.
Decision-making is in the locus of your control. We all have the power to break patterns of behavior simply by making better decisions, but this is often easier said than done. That said, even when you're stuck in a cycle of rut-like thinking and behavior, a change of attitude and decision-making can turn your life around. This new study shows that reducing your anxiety levels might be the first step to starting a life-changing domino effect that empowers you to perpetually make better choices.
Remember, taking a few deep breaths will instantly activate your parasympathetic nervous system and vagus nerve which slows down your heart rate, lowers blood pressure, and puts you in a calmer state of mind. Diaphragmatic breathing is always going to be your best first line of defense for combating anxiety. If you ever find yourself in an overstimulating and stressful situation that requires a rapid-fire decision, I'd recommend that you remember to slow down and take a few deep breaths before planning your course of action.
The new research from Pitt gives us a better understanding of the specific brain mechanics behind anxiety and decision-making. From a clinical perspective, this could lead to better treatments, interventions, and outcomes for a wide range of psychiatric and addictive disorders. Stay tuned!
© 2016 Christopher Bergland. All rights reserved.