Post-training self administration of sugar facilitates cognitive performance of male C57BL/6J mice in two spatial learning tasks

Behav Brain Res. 2009 Mar 2;198(1):98-104. doi: 10.1016/j.bbr.2008.10.016. Epub 2008 Oct 18.

Abstract

Spatial memory can be strengthened by adverse stimuli that activate the stress system, and administration of the stress hormone corticosterone in close-context with the learning task. Less is known about modulation of spatial memory by post-training positive reinforcers (reward). Cognitive performance was assessed in male C57BL/6J mice using two learning tasks: the water maze (WM) and circular hole board (CHB). Sugar was chosen as a post-training reinforcer. We expected that the free access to sugar immediately (0 h) after training would facilitate spatial memory; delayed access to sugar (4h after training) or no sugar served as controls. In both tasks, 0 h sugar mice showed superior performance, indicated by shorter latencies and distances to the trained spatial location. The memory facilitating effect of sugar became visible at distinct times during training: on the CHB from the first trial onwards, in the WM on training days 4 and 5. Sugar-rewarded mice kept their superior performance during the free exploration/swim trial, expressed by more persistent search strategies for the exit hole or platform. Post-training sugar reward in close-context with performance strengthens memory via modulation of consolidation. This finding supports the integrative theory of reinforcement and memory. We suggest that our experimental set-up will allow to differentiate between direct effects on memory and alterations in reward processes in animal models of stress-related diseases.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Carbohydrates / administration & dosage*
  • Cognition / physiology*
  • Discrimination Learning / physiology
  • Exploratory Behavior / physiology
  • Male
  • Maze Learning / physiology
  • Memory / physiology
  • Mice
  • Mice, Inbred C57BL
  • Psychomotor Performance / physiology
  • Reinforcement Schedule
  • Reinforcement, Psychology*
  • Reward*
  • Self Administration
  • Spatial Behavior / physiology*
  • Time Factors

Substances

  • Carbohydrates