Specifying the contributions of the human amygdala to emotional memory: A case study

We examined emotional memory in patient SP, a 54-year-old woman with bilateral damage to the amygdala. Consistent with previous case studies, SP showed deficits on tests of fear conditioning and recognition memory for arousing stimuli. SP's performance on several emotional episodic memory tasks was examined. We found that bilateral damage to the amygdala only leads to deficits on a subset of emotional episodic memory tasks. Specifically, the amygdala does not seem to be involved when episodic memory performance benefits from the valence of the stimuli. However, when episodic memory benefits from arousal, damage to the amygdala leads to a deficit in performance. Based on our results, we postulate that the amygdala is not involved when emotion enhances episodic memory primarily by contributing an organizing principle such as a schema or category. We expect the effects of amygdala damage to be limited to memory tasks affected by the neuromodulatory changes that occur with arousal. The effects of arousal on episodic memory would be most apparent in the rate of forgetting for arousing stimuli, the recall of arousing stimuli that have a weak central theme, and the recognition of details or events associated with arousing stimuli.