Thirty two healthy subjects - 16 males and 16 females - were examined with MRI brain scans during and after they underwent a challenging arithmetic task, under pressure. To increase the stress level, researchers frequently prompted participants for a faster performance and asked them to restart the task if they responded incorrectly.
For a low stress control condition, participants were asked to count backwards without pressure. Researchers found that, in men, stress was associated to increased cerebral blood flow in the right prefrontal cortex and reduced blood flow in the left orbitofrontal cortex. In women, the limbic system - a part of the brain primarily involved in emotion - was activated when they were experiencing stress.
Both men and women's brain activation was found to last beyond the stress task, but the lasting response in the female brain was stronger. Lead author of the study, Dr. J.J. Wang, claims "Knowing that women respond to stress by increasing activity in brain regions involved with emotion, and these changes last longer than in men, may help us begin to explain the gender differences in the incidence of mood disorders."