Our nervous systems were biologically wired to keep fully alive the memory circuits of learned threat and danger for the duration of our lives, guaranteeing that we won’t ignore cues to potentially perilous situations that could threaten our survival.
— Bruce Ecker, Robin Ticic, Laurel Hulley / Psychotherapy Networker

PTSD (Post Traumatic Stress Disorder) is defined by the National Institute of Mental Health as "A disorder that develops in some people who have experienced a shocking, scary, or dangerous event."  People will continue to experience strong reactions to the event even after it has long past.  People who develop PTSD often have trouble sleeping, have flashbacks, and tend to avoid places and situations that would have any related stimuli.  The body reacts to the perceived stress of the original event, and they feel as though they are reliving the trauma again and again. 

Emotional trauma is not limited to the extreme cases of diagnosed PTSD.  Verbal abuse, embarrassment, even being criticized at a vulnerable time, can feel traumatizing and the brain processes that information accordingly.  

"Even highly competent, mature people who are rational in most areas of life can be suddenly undone when a current circumstance—often perfectly innocuous in itself—triggers an ultradurable emotional learning from the past that’s still tightly enmeshed in their neural wiring. Once the implicit memory is triggered, they’re seized by an emotional state that has a life all its own, with no cognitive awareness of why such a reaction is happening. It could be self-criticism or volcanic rage, numbness or raw panic, underachieving or inconsolable sorrow. Regardless, one’s calm, cognitively evolved state of mind is no match for such a flare-up from the emotional implicit memory system." Says an Alternet Article called Advances in psychology offer hope, By Bruce EckerRobin TicicLaurel Hulley / Psychotherapy Networker

The limbic system is one of the oldest parts of the human brain.  Our emotional processing, and ability to create cues to react to situations in order to survive, is part of what makes us human.  Even if the danger is no longer there, we are set up to anticipate the danger that we learned about before.  In this sense, our human brain is functioning quite well!  However, not everything that feels scary is something we need to avoid.  

For example:  "Consider perfectionism as an example of an emotional learning that therapists frequently encounter. Some clients describe clear memories of original experiences in which being imperfect on their part incurred intense shaming or rejection, but they have no awareness of the resulting implicit learning that has since ruled their responses in life—that it’s urgent to be perfect to avoid such suffering. In contrast, other clients are aware of their learned expectation that imperfection is too dangerous to risk, but even when that expectation is triggered, they have no memory of the original life experiences in which that learning formed." -Alternet Article called Advances in psychology offer hope, By Bruce EckerRobin TicicLaurel Hulley

Photo courtesy of NASA, ESA, M. West (ESO, Chile), and CXC_Penn State University_G. Garmire, et al.