When it comes to emotions, the sexes seem to be divided. Stereotypes of men always set them as the rational, cool-headed thinkers, while women are more sympathetic to the emotional plight of others. But are these categories unfounded? Maybe not entirely. A new study, published in Psychoneuroendocrinology and conducted by researchers at the Institut Universitaire en Santé Mentale de Montréal and the University of Montreal, has found that subtle differences in brain function affect how the sexes respond to negative imagery.

For the researchers, the inspiration for their study came from the differences in mental illness among men and women. “Not everyone’s equal when it comes to mental illness,” said Adrianna Mendrek, researcher at the Institut Universitaire En Santé Mentale de Montréal, in a recent press release. “Greater emotional reactivity in women may explain many things, such as their being twice as likely to suffer from depression and anxiety disorders to men.”

Previous research has also given credence to the theory that men and women respond to emotional stimuli differently. In earlier studies, Mendrek and her colleagues found that when men and women looked at negative images, the limbic system in their brains — the emotional and memory center— reacted differently. For the current study, they decided to take this a step further by viewing in more detail how these differences play out in the brains of men and women, and whether hormonal levels affect this psychological processing as well.

For the study, researchers recruited 46 participants (25 female and 21 male) and ruled out potential contributing factors like age differences, education levels, marital status, ethnicity, and socioeconomic status. Each volunteer was given a blood test at the beginning of the study to assess varying levels of estrogen and testosterone in order to see how they contributed to results. After the blood tests, participants were exposed to images that evoked positive, negative, or neutral emotions while undergoing fMRI brain scans. Participants were also asked to review their emotional responses when looking at the images.

Overall, women reported being more reactive to the emotional images. Meanwhile, higher levels of testosterone were most frequently associated with lowered sensitivity to the images, while higher estrogen levels, regardless of the person’s sex, almost always meant increased sensitivity.

When looking at the brain’s reaction to the images, the researchers found that the dorsomedial prefrontal cortex (dmPFC) and amygdala on the right hemisphere of the brain were activated in both sexes when viewing the images. However, the connection between these two parts of the brain was found to be stronger in men, leading to more interaction between the two parts and further decreased sensitivity to emotional stimuli.

The researchers explained that the reactions of amygdala and the dmPFC say a lot about how a person processes emotion. The amygdala is known as the part of the brain that detects threat, and often fires when a person is exposed to fear or sadness, while the dmPFC helps process social interactions and mediates perception, emotions, and reasoning.

“A stronger connection between these areas in men suggests they have a more analytical than emotional approach when dealing with negative emotions,” said Stéphane Potvin, associate professor at the University of Montreal’s Department of Psychiatry. “It is possible that women tend to focus more on the feelings generated by these stimuli, when men remain somewhat ‘passive’ toward negative emotions, trying to analyze the stimuli and their impact.”

Researchers also observed that testosterone made this connection between the amygdala and dmPFC stronger.

Another study conducted in January seemed to find similar results to Mendrek’s team. In an analogous test done by researchers at the University of Basel, women and men were exposed to emotional images while undergoing fMRI scans. The researchers then looked into the brain activity of their 696 participants, finding that the motoric region, an area known for planning and controlling, was more active in women when exposed to emotional imagery. Overall, the researchers concluded that attaching emotions to images may help women create memories more than it does in men.

Mendrek and her team believe evidence from their study illuminates how the male and female brain could operate differently on psychological levels. “There are both biological and cultural factors that modulate our sensitivity to negative situations in terms of emotions,” Mendrek said. She concluded that the next step for their research will be to investigate how hormones affect people’s reactions to different types of emotion, like sadness, fear, and anger.

Source: Mendrek A, Potvin S, Lungu O, et al. Sex differences in effective fronto-limbic connectivity during negative emotion processing. Psychoneuroendocrinology. 2015.