Stress reshapes brain connections and boosts resilience

Stress resilience isn’t a flatline. It’s a flex, according to new research from Florida International University.

Marcelo Bigliassi, assistant professor of psychophysiology, and Ph.D. student Dayanne Antonio thrive in creating stressful environments. They set out to explore how the brain’s internal wiring and a person’s subjective experience of stress interact to determine how they respond to stressful situations. The findings were recently published in the Journal of Applied Physiology.

Study participants plunged one hand into a bucket of ice-cold water. Frigidly cold water. As the seconds ticked by, the body’s stress systems revved up, and their skin began to sweat. A researcher stared at them intently. Uncomfortably. Nearby, a monitor recorded the participant’s brain waves in real time. The challenge was to keep their hand in the ice-cold water for as long as possible — up to 3 minutes. To keep it unpredictable, participants weren’t told the time limit in advance. The researcher asked questions about their stress, their pain, and their mood before and after the experience. The research team wanted to explore why some people tap out after one minute while others push through for the full three minutes.

The expectation might be that the people who feel the most pain would be the first to quit, but that wasn’t the case. In this study, people who reported higher stress and higher pain often lasted longer, suggesting tolerance under stress isn’t the absence of discomfort, but what people do with it. Some participants got used to the pain, allowing their bodies to adapt to the stress. The researchers say this could be due to a phenomenon called "stress-induced analgesia." When the body recognizes a major challenge, it can trigger a natural release of painkillers, like endorphins, helping the individual embrace the discomfort to reach a goal.

While feeling the stress helped, what separated the people who lasted from those who stopped wasn’t simply how intense the stress felt — it was how the brain’s control network handled it, the researchers say. Using EEG to track the frontoparietal network (the brain’s command center) for focus and self-regulation, the researchers found a hidden obstacle to resilience. People who showed a more uneven, one-directional pattern in brain communication tended to quit earlier. Averaged across the task, the research team observed reduced directed connectivity, so tolerance may be less about forcing control and more about adapting it. In other words, when the brain tries too hard to force control, it may become brittle and less able to adapt. In contrast, those who remained cognitively flexible, using strategies like paced breathing, shifting attention away from the pain, encouraging self-talk, and quick reappraisals, were able to stay engaged even when the urge to pull away was strong.

“We see signs that stress may involve dynamic shifts in control-network connectivity, possibly an early suppression followed by re-engagement in those who persist longer,” Bigliassi said. “But testing those moment-to-moment changes will require time-resolved modeling in future studies.”

The body’s stress response also had a clear signature — skin conductance rose sharply, peaked early, and then gradually declined, suggesting adaptation unfolding in real time, even while the stressor remained present. The findings can have major implications for how people train and prepare for sports, high-risk careers, and other stressful environments.

“People often struggle with managing stress,” Bigliassi said. “I believe we can harness stress. We need to discover how individuals can use stress to their benefit.”