A memory-enhancing emotionally arousing narrative increases blood glucose levels in human subjects

Abstract

To examine the contribution of glucose to the memory-enhancing effects of emotional arousal, we determined whether a memory-enhancing emotional narrative would increase blood glucose levels. Blood glucose was measured before and after participants viewed slides accompanied by a neutral or an emotionally arousing narrative. Prior to the slide show, the participants drank a beverage containing either glucose or saccharin. Participants who heard the emotionally arousing narrative had better memory of the narrative and slide show 2 weeks later than did participants who heard the neutral narrative. Blood glucose levels increased after the emotionally arousing narrative, but not after the neutral narrative. Glucose administration produced a larger increase in blood glucose levels than did the emotionally arousing narrative and prevented the memory-enhancing effect of emotional arousal. These findings indicate that small increases in blood glucose levels may contribute to the memory-enhancing effects of emotional arousal, whereas larger glucose increases may prevent its effects.