My understanding of the article and findings Trace is that they have discovered that when the brain experiences a trauma/threat a change takes place in the brain where if a reminder is presented the brain doesn't produce the chemical that reduces the sense of urgency the reminder triggers. By understanding what actually happens in the brain we can look for ways to reduce the level of stress experienced by the individual so they can function better without "reacting" to reminders as if the danger is a threat in the "now".

This is something "IMO" that takes place to ensure survival as well as a desire to sound an alarm and focus on the danger in an effort to find ways to overcome that danger better.

With human beings however, this can be a lot more complex simply because we have evolved into complex intelligent beings compared to other mammals and life forms.