The Effect on Memory
When humans take in new information- whether it’s a phone number, or seeing someone killed- the memory is “labile” at first, or chemically unstable.
But at some point within the next six hours, a flood of proteins produced by the brain moves the memory from short-term to long-term imprint.
The brain’s wiring changes each time something goes into long-term memory, but not all memories are equal. “You remember the day of your wedding better than three Tuesdays ago when there was nothing important going on.”
Emotional memories activate a second process that ups their intensity. This is called a “gain switch”. With PTSD, this gain switch just gets turned way up after trauma. So now what happens is that people are just overwhelmed by their emotional memories.
Studies have shown that emotionally arousing events cause stress-related hormones such as adrenaline to be released by the brain’s amygdale, which is involved in emotional learning and memory. PTSD may develop when the event is so emotionally powerful, and so much adrenalin is released, that the “gain-switch” is set too high.
Then, each time the traumatic experience is recalled; the amygdale releases yet more hormones and intensifies the stressful memories even more.
