Jenny Diski reviews Memory: Fragments of a Modern History by Alison Winter:
It seems that the emotion of an event is stored separately (in the amygdala) from the recollection of the event itself (in the hippocampus), and that traumatic memories are physiologically different from the regular sort. A traumatic experience is accompanied by a surge of adrenal stress hormones which increases the strength of the memory, and each time the event is recalled, a renewed rush of epinephrine and cortisol reinforces the event’s emotional impact and its ease of recall.
The Dish 