Brain's Courage Center Located

The ability to conquer fears may come down to activity in a certain region of the brain, a new study suggests.

The study's researchers say it is the first to investigate brain changes that occur when humans act courageously — that is, when we feel fear, yet act in a manner that opposes this fear.

The results show activity in a brain region called the subgenual anterior cingulate cortex (sgACC) was associated with participants overcoming their fears, suggesting this brain region could be a target for therapies for phobias and fear-related disorders.

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"We think this activity of the sgACC, in a way, reflects the effort of the person to overcome his fears," said study researcher Uri Nili, at the Weizmann Institute of Science in Rehovot, Israel.

"This suggests that maybe by enhancing in some way the activity in this region you might be able to aid these people in instances where they need to overcome fear and currently cannot do that," Nili said.

Snakes on a conveyer belt

Participants were asked to literally face their fear of snakes in this study, which included 39 participants who scored within the top 20 percent of subjects on a questionnaire designed to gauge people's fear of snakes. The study also included 22 participants who had handled snakes and were not afraid of them.

In the experiment, either a live snake or a toy bear was placed in a conveyer belt (the toy bear was a control, an object people don't typically fear). The subjects, lying in a functional magnetic resonance imaging (fMRI) scanner, pressed a button that would bring the snake or the bear one step closer to their head. With each "advance" or "retreat" selection, the participants were asked to report their fear level.

The subjects were told to try to bring the snake or toy bear as close to their head as possible.

Not surprisingly, no one was afraid of the bear — participants always chose the "advance" option in this situation. Those with no fear of snakes treated the snakes the same as the toy bear. Some with snake phobia often chose the "advance" option, while others tended to choose "retreat."

Activity in the sgACC was higher when the subjects chose to advance the snake, and lower when they chose to retreat.

Also, the more activity the participants had in their sgACC, the higher their reported level of fear, but only in instances where the subjects overcame their fear and brought the snake closer.

When the subjects succumbed to their fear, and moved the snake farther away, activity in this region dipped, although their reported level of fear was high. This means sgACC activity was not simply reflecting their fear level, but rather, the effort it took to overcome it, Nili said. 

How it works

The researchers also measured the participants "skin conductance response," intended to gauge their arousal level, a physiological response to fear and other emotions.

In general, a higher level of fear means a greater skin conductance response. Indeed, the researchers saw this was true in cases where fearful participants decided to move the snake farther away.

But when bringing the snake closer, a high fear level was associated with low arousal.

So if the subjects were afraid, why didn't their bodies show it?

That's where the sgACC comes in. The researchers think activity in the sgACC acts to suppress the psychological response to fear, and thus allow people to act courageously, Nili said.

The results are published in June 24 issue of the journal Neuron.

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