How the brain keeps emotions at bay

Sep 20, 2006

Daily life requires that people cope with distracting emotions--from the basketball player who must make a crucial shot amidst a screaming crowd, to a salesman under pressure delivering an important pitch to a client. Researchers have now discovered that the brain is able to prevent emotions from interfering with mental functioning by having a specific "executive processing" area of the cortex inhibit activity of the emotion-processing region.

The findings also offer insight into how sufferers of post-traumatic stress disorder (PTSD) or depression are unable to control emotional intrusion into their thoughts, said the researchers, Amit Etkin, Joy Hirsch, and colleagues, who reported the discovery. They published their findings in the September 21, 2006, issue of the journal Neuron, published by Cell Press.

Their studies were based on previous findings that specific parts of an area of the brain called the anterior cingulate cortex (ACC)--a center for so-called "executive" control of neural processing--are connected to the amygdala. The amygdala is the brain's major center for processing emotional events.

The experimental challenge for Etkin, Hirsch, and colleagues was to determine whether this region of the ACC was responsible merely for "monitoring" conflict between cognitive and emotional processing or for actively "resolving" that conflict.

To distinguish the two processes, Etkin and colleagues designed experiments in which volunteer subjects were asked to indicate by pressing a button whether a face image was happy or fearful. The subjects were instructed to ignore labels of "fear" or "happy" written across each face.

These labels might be either "congruent" (e.g., happy face, "happy" word) or "incongruent" (e.g., happy face, "fear" word) with the image. Incongruent face-word combinations constituted a response conflict between emotional and cognitive stimuli. The researchers found that subjects could "resolve" this conflict more readily if an incongruent image was preceded by another incongruent image. This resolution represented an anticipation by the subjects' brains from the first image that they could resolve the conflict depicted in the second image

As the researchers scanned the subjects' brains with functional magnetic resonance imaging (fMRI), they presented the subjects with a series of such images designed to reveal what parts of the brain were active during such conflict resolution. The technique of fMRI involves using harmless magnetic fields and radio waves to measure blood flow in brain regions, which reflects brain activity.

Etkin, Hirsch, and colleagues found that the emotional stimuli activated the amygdala as expected. Importantly, they found that when presented with the "incongruent" images this activity was inhibited by specific activation of the "rostral ACC" in a manner that indicated this region was exerting inhibitory control over the amygdala.

"Our experiments on healthy subjects were carried out in order to understand what role the rostral cingulate normally plays in nonpathological emotional conflict," wrote the researchers. "But the data also allow us to better understand a variety of psychiatric disorders in which patients experience exaggerated interference from emotional distracters." They pointed out that people with PTSD, as well as those whose depression is resistant to treatment, show lowered rostral cingulate activity during emotional processing. "Indeed, lower rostral cingulate activity prior to treatment actually predicts a poor response to antidepressant therapy," they wrote.

"Taken together, these findings suggest that elevated amygdalar activity and exaggerated behavioral interference may be due to deficient amygdalar inhibition by the rostral cingulate, which leads to an inability to deal with emotional conflict," concluded Etkin and colleagues. "The capacity for recruitment of the rostral cingulate may thus determine how well an individual can cope with the intrusion of negative emotional stimuli or mental content," they concluded.

Source: Cell Press

Explore further: Life-prolonging protein could inhibit ageing diseases

Related Stories

Thinking alike changes the conversation

May 19, 2015

As social creatures, we tend to mimic each other's posture, laughter, and other behaviors, including how we speak. Now a new study shows that people with similar views tend to more closely mirror, or align, ...

We must defend science if we want a prosperous future

Mar 03, 2015

Today's Australians are, by far, the best educated cohort in our history –- on paper, anyway -– but this is not reflected in the quality of our political discourse. We appear to be lacking in courage, ...

Brain activity exposes those who break promises

Dec 09, 2009

Scientists from the University of Zurich have discovered the physiological mechanisms in the brain that underlie broken promises. Patterns of brain activity even enable predicting whether someone will break a promise. The ...

Beyond human: Exploring transhumanism

Nov 25, 2014

What do pacemakers, prosthetic limbs, Iron Man and flu vaccines all have in common? They are examples of an old idea that's been gaining in significance in the last several decades: transhumanism. The word ...

Recommended for you

Life-prolonging protein could inhibit ageing diseases

May 29, 2015

Researchers have found a molecule that plays a key link between dietary restriction and longevity in mammals. This discovery may lead to the development of new therapies to inhibit age-related diseases.

How sleep helps us learn and memorize

May 28, 2015

Sleep is important for long lasting memories, particularly during this exam season. Research publishing in PLOS Computational Biology suggests that sleeping triggers the synapses in our brain to both streng ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.