Clinicians diagnose Post Traumatic Stress Disorder, or PTSD, based on a series of criteria. An important one of these states that PTSD comes about after someone experiences “intense fear, helplessness or horror” in response to a traumatic event. One popular theory of PTSD is that the amygdala, as the brain seat of fear, is not regulated well.

I have a vision of psychology professor Lisa Feldman Barrett sitting at her desk reading that line in the Diagnostic and Statistical Manual of Mental Disorders and slapping her forehead in frustration. Barrett has spent the last decade pushing against the commonly held idea that emotions are localized to particular areas of the brain and that they are the sort of “subatomic particles” of psychology.

Despite tons of evidence that the amygdala is active in all sorts of emotional responses, from fear to anger to sadness, as well in social processing and vision more broadly, and it is still widely believed to be the “fear” area of the brain. And since PTSD is thought to be a “fear disorder,” clinicians and some scientists think it is a disorder of the amygdala, too.

In an article published last year — which was the most downloaded from the Journal of Traumatic Stress in 2011 — Barrett and her colleague Michael Suvak, a PTSD expert at the VA Boston Healthcare System, apply what Barrett calls a “constructionist approach” to understanding the disorder.

The psychological construction approach proposes that phenomena like emotions, cognition and perception are not the fundamental elements of the mind, associated with distinct brain regions. Instead, the authors write in the article, they “are the names people give to mental events that result from the interplay of a more basic, common set of psychological ingredients.” These ingredients, they hypothesize, are networks of brain activity that correspond to things like affect, conceptualization, and executive function.

Instead of labeling PTSD as a “fear disorder,” the sought-after paper suggests it might be more useful to think of it as a disorder of one or more of these functional networks. For example, it could be that for people who develop PTSD “information from the world has stronger affective value,” say the authors. “It is more motivationally salient and homeostatically relevant, even when it ought not to be.”

Looking at PTSD from this perspective resolves some of the long-considered mysteries about the disorder, namely that an individual can develop PTSD without experiencing the emotions of “fear” and “anxiety” and that multiple brain regions seem to be hyper- or hypo-active in PTSD individuals, not just the amygdala.

With PTSD gaining more attention in the media, in society and in the research world, understanding the disorder at its roots will be of particular importance.