Epinephrine enhancement of human memory consolidation: Interaction with arousal at encoding

• Published in: Neurobiology of learning and memory Vol. 79; no. 2; pp. 194 - 198
• Main Authors: Cahill, Larry, Alkire, Michael T.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Inc 01.03.2003; Elsevier
• Subjects: Adult; Arousal - drug effects; Arousal - physiology; Behavioral psychophysiology; Biological and medical sciences; Dose-Response Relationship, Drug; Epinephrine - administration & dosage; Epinephrine - pharmacology; Epinephrine - physiology; Female; Fundamental and applied biological sciences. Psychology; Galvanic Skin Response - drug effects; Heart Rate - drug effects; Human; Humans; Injections, Intravenous; Learning. Memory; Male; Memory; Memory - drug effects; Memory - physiology; Neurotransmission and behavior; Personality. Affectivity; Psychology. Psychoanalysis. Psychiatry; Psychology. Psychophysiology; Retention (Psychology) - drug effects; Retention (Psychology) - physiology; Stress; Sympathomimetics - administration & dosage; Sympathomimetics - pharmacology; Epinephrine; Human; Memory retrieval; Memory; Cognition; Catecholamine; Experimental study; Stress; Dose activity relation; Visual stimulus; Acquisition process; Consolidation; Information processing
• ISSN: 1074-7427; 1095-9564
• DOI: 10.1016/S1074-7427(02)00036-9

Abundant evidence indicates that endogenous stress hormones like epinephrine and cortisol modulate memory consolidation in animals. Despite this evidence, there has been no demonstration that endogenous stress hormones modulate memory consolidation in humans. In the present study, healthy subjects viewed a series of 21 slides, and immediately after received an intravenous infusion of either saline or epinephrine (40 or 80 ng/kg/min). Memory for the first three (primacy) and last three (recency) slides viewed was assessed with an incidental free recall test one week later. Epinephrine dose-dependently increased memory for the primacy slides, but did not affect memory of the recency slides. A subsequent experiment involving new subjects revealed significantly higher electrodermal responses to the primacy compared with recency slides. These findings support the view ( Gold & McGaugh, 1975) that endogenous stress hormones modulate memory consolidation for experiences that induce their release. Additionally, they suggest that in humans these hormones may interact with the degree of arousal at initial encoding of information to modulate memory consolidation processes for that information.