Theta resynchronization during reconsolidation of remote contextual fear memory.
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.
Narayanan
Rajeevan T
RT
Institute of Physiology I, Westfälische Wilhelms--University Münster, Münster, Germany.
Seidenbecher
Thomas
T
Sangha
Susan
S
Stork
Oliver
O
Pape
Hans-Christian
HC
D000818:Animals; D001362:Avoidance Learning; D001522:Behavior, Animal; D001921:Brain / Q000033:anatomy & histology / Q000502:physiology*; D004597:Electroshock / Q000009:adverse effects; D005239:Fear / Q000502:physiology*; D046352:Freezing Reaction, Cataleptic / Q000502:physiology / Q000528:radiation effects; D008297:Male; D011939:Mental Recall / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D013057:Spectrum Analysis; D013826:Theta Rhythm; D013997:Time Factors