Theta resynchronization during reconsolidation of remote contextual fear memory

Neuroreport. 2007 Jul 16;18(11):1107-11. doi: 10.1097/WNR.0b013e3282004992.


We have recently demonstrated high theta-phase synchronization between the lateral amygdala and CA1 area of the hippocampus during retrieval of long-term (1 day) fear memory, and not during short-term (2 h) or remote memory retrieval (30 days). These results indicated that the amygdalo-hippocampal interaction reflects a dynamic change of ensemble activities related to various stages of fear memory storage. In this study, we investigated theta activity during the reconsolidation of a remote contextual fear memory by re-exposing animals to the shock context 30 days after training. Consistent with our previous results, high theta synchronization was no longer apparent during re-exposure to the shock context, but was significantly higher 1 day after context re-exposure. These data indicate that the reconsolidation of remote contextual fear memory includes changes in ensemble activities between the lateral amygdala and CA1.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Avoidance Learning
  • Behavior, Animal
  • Brain / anatomy & histology
  • Brain / physiology*
  • Electroshock / adverse effects
  • Fear / physiology*
  • Freezing Reaction, Cataleptic / physiology
  • Freezing Reaction, Cataleptic / radiation effects
  • Male
  • Mental Recall / physiology*
  • Mice
  • Mice, Inbred C57BL
  • Spectrum Analysis
  • Theta Rhythm*
  • Time Factors