Brain on Fire: My Month of Madness

by Susannah Cahalan

The amygdala, an almond-shaped structure situated atop the hippocampus, located at the sides of the head above the ears in the temporal lobes, is a structure intimately involved in emotion and memory, helping to choose which memories should be kept and which should be discarded, based on which events have traumatized or excited us. The hippocampus tags the memory with context (the hospital room and the purple lady, for example), and the amygdala provides the emotion (fear, excitement, and pain). When the amygdala stamps the experience with high emotional value, it’s more likely to be preserved, a process called encoding, and eventually made into a memory, called consolidation. The hippocampus and amygdala help encode and consolidate the experience, or make it into a memory that can be retrieved later. When any part of this elaborate system is compromised, the memory may not be formed.