Effect of reversible inactivation of the reuniens nucleus on spatial learning and memory in rats using Morris water maze task

Behav Brain Res. 2009 Mar 2;198(1):130-5. doi: 10.1016/j.bbr.2008.10.037. Epub 2008 Nov 6.


The involvement of thalamic midline nuclei (MLN) in early stage of Alzheimer's disease and in diencephalic amnesia has drawn attention to the connectivity between the nucleus reuniens (RE) and structures of medial temporal lobe. RE is major source of thalamic afferents to the hippocampus and has been shown to exert powerful excitatory action on CA1 of hippocampus, which is supposed to be involved in learning and memory processes. However, the role of the RE on spatial memory is a controversial issue. The present study was designed to evaluate the role of the RE in acquisition, consolidation and retrieval of spatial reference memory (RM) and working memory (WM). We assessed the effect of reversible inactivation of RE with tetracaine (0.5 microl, 2%) on different stages of memory. Rats were trained on RM and WM versions of the Morris water maze (MWM) task. RE was inactivated before or immediately after training or before the probe trial of retrieval tests. The data showed that reversible inactivation of the RE significantly impaired both RM and WM versions of MWM. Therefore, it seems that nucleus reuniens of thalamus plays a role in spatial RM and WM version of the MWM task in rats.

MeSH terms

  • Anesthetics, Local / administration & dosage
  • Anesthetics, Local / toxicity
  • Animals
  • Escape Reaction / physiology
  • Exploratory Behavior / drug effects
  • Exploratory Behavior / physiology
  • Male
  • Maze Learning / drug effects
  • Maze Learning / physiology*
  • Memory / drug effects
  • Memory / physiology*
  • Microinjections / methods
  • Midline Thalamic Nuclei / cytology
  • Midline Thalamic Nuclei / drug effects
  • Midline Thalamic Nuclei / physiology*
  • Neural Pathways / anatomy & histology
  • Neural Pathways / physiology
  • Rats
  • Rats, Wistar
  • Spatial Behavior / drug effects
  • Spatial Behavior / physiology*
  • Swimming
  • Tetracaine / administration & dosage
  • Tetracaine / toxicity
  • Thalamus / cytology
  • Thalamus / drug effects
  • Thalamus / physiology


  • Anesthetics, Local
  • Tetracaine