Acute effects of alcohol on intrusive memory development and viewpoint dependence in spatial memory support a dual representation model

Biol Psychiatry. 2010 Aug 1;68(3):280-6. doi: 10.1016/j.biopsych.2010.01.010. Epub 2010 Mar 3.

Abstract

Background: A dual representation model of intrusive memory proposes that personally experienced events give rise to two types of representation: an image-based, egocentric representation based on sensory-perceptual features; and a more abstract, allocentric representation that incorporates spatiotemporal context. The model proposes that intrusions reflect involuntary reactivation of egocentric representations in the absence of a corresponding allocentric representation. We tested the model by investigating the effect of alcohol on intrusive memories and, concurrently, on egocentric and allocentric spatial memory.

Methods: With a double-blind independent group design participants were administered alcohol (.4 or .8 g/kg) or placebo. A virtual environment was used to present objects and test recognition memory from the same viewpoint as presentation (tapping egocentric memory) or a shifted viewpoint (tapping allocentric memory). Participants were also exposed to a trauma video and required to detail intrusive memories for 7 days, after which explicit memory was assessed.

Results: There was a selective impairment of shifted-view recognition after the low dose of alcohol, whereas the high dose induced a global impairment in same-view and shifted-view conditions. Alcohol showed a dose-dependent inverted "U"-shaped effect on intrusions, with only the low dose increasing the number of intrusions, replicating previous work. When same-view recognition was intact, decrements in shifted-view recognition were associated with increases in intrusions.

Conclusions: The differential effect of alcohol on intrusive memories and on same/shifted-view recognition support a dual representation model in which intrusions might reflect an imbalance between two types of memory representation. These findings highlight important clinical implications, given alcohol's involvement in real-life trauma.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptation, Psychological / drug effects*
  • Adolescent
  • Adult
  • Analysis of Variance
  • Central Nervous System Depressants / pharmacology*
  • Dose-Response Relationship, Drug
  • Double-Blind Method
  • Ethanol / pharmacology*
  • Female
  • Humans
  • Male
  • Memory / drug effects*
  • Models, Psychological
  • Recognition, Psychology / drug effects*
  • Reference Values
  • Repression, Psychology
  • Stress Disorders, Post-Traumatic / physiopathology
  • Stress Disorders, Post-Traumatic / psychology*
  • Young Adult

Substances

  • Central Nervous System Depressants
  • Ethanol