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Published on: January 1, 2018
Basolateral amygdala stimulation does not recruit LTP at depotentiated synapses.
W Almaguer-Melian1, J A Bergado, L Martínez-Martí
1International Centro for Neurological Restoration (CIREN), 11300 Havana, Cuba.
Physiology & Behavior
|July 30, 2010
Summary
Basolateral amygdala (BLA) stimulation cannot reverse depotentiation of hippocampal long-term potentiation (LTP) in the dentate gyrus. This suggests BLA stimulation does not reactivate synaptic tags after depotentiation, failing to restore memory formation.
Area of Science:
- Neuroscience
- Cellular and Molecular Biology
- Cognitive Science
Background:
- Long-term potentiation (LTP) in the hippocampus is crucial for memory formation.
- LTP has two phases: early (E-LTP, protein synthesis-independent) and late (L-LTP, protein synthesis-dependent).
- Basolateral amygdala (BLA) stimulation can reinforce E-LTP into L-LTP, a process termed structural LTP-reinforcement.
Purpose of the Study:
- To investigate if BLA stimulation can recover LTP after depotentiation.
- To test the hypothesis that BLA stimulation can reactivate synaptic tags reset by depotentiation.
- To determine if BLA stimulation can convert depotentiated E-LTP back into L-LTP.
Main Methods:
- Induction of E-LTP in the dentate gyrus (DG) of freely moving rats.
- Depotentiation of induced E-LTP using low-frequency stimulation (LFS).
- Post-depotentiation stimulation of the BLA.
Main Results:
- BLA stimulation was ineffective in recovering LTP at depotentiated synaptic inputs in the DG.
- The results indicate that BLA stimulation did not reactivate synaptic tags that were reset by depotentiation.
- The conversion of E-LTP to L-LTP via BLA stimulation was not observed after depotentiation.
Conclusions:
- BLA stimulation cannot restore hippocampal LTP once it has been depotentiated.
- Synaptic tags, if reset by depotentiation, are not reactivated by subsequent BLA stimulation.
- The findings challenge the proposed mechanism of structural LTP-reinforcement involving tag reactivation after depotentiation.
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