Anxiety avoidance and the brain

The excellent Anxiety series from The New York Times recently included a piece called "For the Anxious, Avoidance Can Have an Upside" by Joseph LeDoux, a neuroscientist I've referred to a number of times in the past here on PANIC! The article posits that avoidance isn't always maladaptive:

...people with social anxiety often cope with their problem by avoiding social situations altogether.  This is not practical or beneficial.  But neither is forcing oneself to show up at parties and just try to ride out the anxiety.  A more effective treatment approach might be to combine anxiety-producing exposure with strategies that allow one to gain control over the anxiety trigger cues.

Michael Rogan, who was a researcher in my lab when the active coping work was first being done, currently treats people with social anxiety. He suggests to his clients with social anxiety that they should, when at a party, identify strategies for temporary escape and avoidance (go into the bathroom, step outside to make a call), and also use previously learned relaxation techniques (controlled breathing, imagery, mindfulness), to “chill out.” In this way, as in the rat studies, behaviors that succeed in reducing anxiety are reinforced, and each subsequent social event is a bit more tolerable.

Here's how it works in the brains of rats (and by implication in the human brain), according to LeDoux:

Much has been learned about the brain mechanisms underlying passive and active coping in rats.  Freezing, the rat’s version of passive coping, is known to depend on a specific set of connections in the brain — specifically, between two regions of the amygdala: the one that processes incoming signals about the external world and the one that regulates innate reactions like freezing (via outputs to the lower brainstem). The active coping response, proactive avoidance, by contrast, requires that the information processed in the input region be redirected to a different output controller in the amygdala, one that engages goal-directed actions.... 

A major conceptual issue is how the re-routing takes place naturally within the amygdala, allowing the shift from freezing to active coping and thereby preventing pathological avoidance and allowing proactive avoidance and agency.  Recent work has shown that connections from the prefrontal cortex, a region important in behavioral control, to the amygdala are important in allowing the shift to take place. 

The amygdala has long been thought of as the accelerator on the threat train, and the prefrontal cortex the brakes.  But the new work suggests that the prefrontal cortex is not just the brakes, but also the switch that controls the track on which the train travels.  Figuring out how to more effectively engage the prefrontal cortex in this switching will hopefully suggest new treatment approaches.