Why we fight: Men check out in stressful situations

September 28, 2010

A new study by USC researchers reveals that stressed men looking at angry faces had diminished activity in the brain regions responsible for understanding others' feelings.

Turns out the silent and stoic response to stress might be a guy thing after all.

"These are the first findings to indicate that sex differences in the effects of stress on social behavior extend to one of the most basic social transactions -- processing someone else's facial expression," said Mara Mather, director of the Emotion and Cognition Lab at USC.

In an article appearing the October 6 issue of the journal NeuroReport, Mather and her coauthors present a series of tests indicating that, under acute stress, men had less brain response to facial expressions, in particular, fear and anger.

In both men and women, looking at pictures of faces caused activity in the part of the brain used in basic visual processing (the "fusiform face area") and in parts of the brain used for interpreting and understanding facial expressions.

However, men under acute stress showed decreased activity not only in the fusiform face area but also decreased coordination among parts of the brain that help us interpret what emotions these faces are conveying.

In a marked sex difference, women under stress showed the opposite -- women under stress had increased activity in the fusiform face area and increased coordination among the regions of the brain used in interpreting facial emotions compared to the control group.

Cortisol levels, a known indication of stress, were manipulated using the cold pressor stress test, with no significant sex differences in baseline cortisol or degree of cortisol change.

Men and women under stress were as adept as those in the control group at remembering the faces.

"The study indicates that experiencing acute stress can affect subsequent activity and interactions in brain regions in opposite ways for males and females," said Mather, associate professor of gerontology and psychology in the USC Davis School of Gerontology and the USC College of Letters, Arts and Sciences.

"Under stress, men tend to withdraw socially while women seek emotional support," Mather said.

Prior research has shown the crucial role of the insula in helping us simulate the experiences of others, while the temporal pole has been shown to be important for understanding the emotions of others. Both are part of a known circuit -- along with the inferior frontal region and the amygdala -- that contribute to empathy and social understanding.

The study looked at forty-seven right-handed non-smokers. All participants were asked to refrain from exercise or caffeine in the hour before the study and none of the participants were on hormone birth control or steroid medications.
-end-
Nichole Lighthall and Lin Nga of the USC Davis School of Gerontology, and Marissa Gorlick of the University of Texas also contributed to the study, which was supported by a grant from the National Institute on Aging.

Mather et. al, "Sex differences in how stress affects brain activity during face viewing." NeuroReport: October 2010.

University of Southern California

Related Stress Articles from Brightsurf:

Stress-free gel
Researchers at The University of Tokyo studied a new mechanism of gelation using colloidal particles.

Early life stress is associated with youth-onset depression for some types of stress but not others
Examining the association between eight different types of early life stress (ELS) and youth-onset depression, a study in JAACAP, published by Elsevier, reports that individuals exposed to ELS were more likely to develop a major depressive disorder (MDD) in childhood or adolescence than individuals who had not been exposed to ELS.

Red light for stress
Researchers from the Institute of Industrial Science at The University of Tokyo have created a biphasic luminescent material that changes color when exposed to mechanical stress.

How do our cells respond to stress?
Molecular biologists reverse-engineer a complex cellular structure that is associated with neurodegenerative diseases such as ALS

How stress remodels the brain
Stress restructures the brain by halting the production of crucial ion channel proteins, according to research in mice recently published in JNeurosci.

Why stress doesn't always cause depression
Rats susceptible to anhedonia, a core symptom of depression, possess more serotonin neurons after being exposed to chronic stress, but the effect can be reversed through amygdala activation, according to new research in JNeurosci.

How plants handle stress
Plants get stressed too. Drought or too much salt disrupt their physiology.

Stress in the powerhouse of the cell
University of Freiburg researchers discover a new principle -- how cells protect themselves from mitochondrial defects.

Measuring stress around cells
Tissues and organs in the human body are shaped through forces generated by cells, that push and pull, to ''sculpt'' biological structures.

Cellular stress at the movies
For the first time, biological imaging experts have used a custom fluorescence microscope and a novel antibody tagging tool to watch living cells undergoing stress.

Read More: Stress News and Stress Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.