Paulus and Simmons tested 10 of the world's most accomplished adventure racers—men and women who perform wilderness challenges that can include climbing, swimming, running and paddling. They asked the racers and 11 healthy control subjects to lie in a scanner and breathe through a tube while wearing a nose clip. While in the magnetic resonance imaging (MRI) machine, the subjects were instructed to view arrows pointing either left or right on a screen and press a button to note the direction. Sporadically, the researchers adjusted the airflow so that breathing became significantly more difficult. A change in the screen's color alerted the participants that breathing was about to become labored. The color change did not always accurately predict breathing restriction, however.
In all phases of the experiment, the insula was active, but to varying degrees. The healthy volunteers performed equally well on the arrow tests throughout the study—with no interference, when the screen’s color changed and when struggling to inhale. But the adventure racers got more answers correct when either anticipating or undergoing the breathing load. Perturbing these individuals' interoceptive experience actually improved their performances. The racers also showed more brain activation when anticipating the breathing restriction but not while experiencing the restriction itself. It was as if the racers' brains made better use of cues to prepare themselves, thus gaining a cognitive edge. When the challenging moment arrived—when their breathing became labored—their insulas were comparatively placid.
Another study from Paulus's group, also published in 2012, adds nuance to this finding. The group sought to investigate elite athletes' cognitive flexibility. Considered a landmark of intelligence, this skill involves switching easily between opposing demands. Mental agility can plummet in a trying situation, however. Experiments on Navy SEALs and Army Rangers revealed that exposure to combatlike conditions impaired their reaction times, vigilance, learning, memory and reasoning. For Olympic-level athletes, too, grace under fire is a major objective.
To observe cognitive flexibility in action, Simmons asked 10 Navy SEALs and 11 healthy male civilians to perform a simple task in a brain scanner. Navy SEALs are extremely athletic individuals who are trained to cope with great demands on their physical, mental and emotional faculties. The exercise involved observing either a green or red shape followed by an emotionally laden photograph on a screen. Participants were to press one button when they saw a circle and another when they viewed a square. A green shape signaled that a positive image (such as a child playing) would follow; a red shape indicated that a negative picture (for example, a combat scene) would appear next. The subjects were then judged on their speed and accuracy in identifying the shapes.
Compared with healthy participants, the elite warriors sent more blood coursing through their insulas and a few other regions when the shapes' colors differed in consecutive trials. In short, they were more aware of the impending switch from positive to negative or vice versa and engaged brain systems involved in modulating emotional and interoceptive responses. They were quicker to prepare for a looming shift in their internal states, buying their brains time to tamp down their reactions.
Taken together, the studies indicate that men and women who have extreme physical abilities show greater insula activation when anticipating a change to their internal feelings, whether emotional or physical.
"To me that's really huge if you have a region of the brain that's anticipating a response and preparing the body for it," physiologist Jon Williamson at the University of Texas Southwestern Medical Center says. "If an athlete is approaching a hill and can anticipate the delivery of blood to muscles, he or she may perform better on that hill."