Relationship of enhanced norepinephrine activity during memory consolidation to enhanced long-term memory in humans

Am J Psychiatry. 2002 Aug;159(8):1420-2. doi: 10.1176/appi.ajp.159.8.1420.


Objective: The purpose of this study was to investigate the effect of enhanced noradrenergic activity on memory consolidation in humans.

Method: Thirty healthy subjects (21 men and nine women) viewed a series of 12 slides that depicted an emotionally arousing story. Five minutes after viewing the slides, subjects received either intravenous yohimbine or intravenous placebo in a double-blind randomized fashion. Multiple blood samples were drawn for determining plasma free 3-methoxy-4-hydroxyphenylglycol (MHPG). One week later subjects took a surprise memory test for the slides.

Results: There was no significant difference in memory score between yohimbine and placebo groups. Linear regression revealed a significant effect of MHPG on memory score for the group as a whole (subjects who had received yohimbine and those who had received placebo) and for the placebo group alone.

Conclusions: These findings strengthen support for the hypothesis that enhanced memory for emotionally arousing events in humans depends critically on postlearning adrenergic modulation.

Publication types

  • Clinical Trial
  • Comparative Study
  • Randomized Controlled Trial
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Adult
  • Double-Blind Method
  • Emotions / physiology*
  • Female
  • Humans
  • Infusions, Intravenous
  • Linear Models
  • Male
  • Memory / drug effects
  • Memory / physiology*
  • Mental Recall / drug effects
  • Mental Recall / physiology
  • Methoxyhydroxyphenylglycol / blood
  • Middle Aged
  • Norepinephrine / metabolism
  • Norepinephrine / physiology*
  • Placebos
  • Psychological Tests
  • Stress Disorders, Post-Traumatic / diagnosis
  • Stress Disorders, Post-Traumatic / psychology
  • Visual Perception / physiology
  • Yohimbine / administration & dosage
  • Yohimbine / pharmacology


  • Placebos
  • Yohimbine
  • Methoxyhydroxyphenylglycol
  • Norepinephrine