Inactivation of the dorsal hippocampus or the medial prefrontal cortex impairs retrieval but has differential effect on spatial memory reconsolidation.
Active memories can incorporate new information through reconsolidation. However, the notion that memory retrieval is necessary for reconsolidation has been recently challenged. Non-reinforced retrieval induces hippocampus and medial prefrontal cortex (mPFC)-dependent reconsolidation of spatial memory in the Morris water maze (MWM). We found that the effect of protein synthesis inhibition on this process is abolished when retrieval of the learned spatial preference is hindered through mPFC inactivation but not when it is blocked by deactivation of dorsal CA1. Our results do not fully agree with the hypothesis that retrieval is unneeded for reconsolidation. Instead, they support the idea that a hierarchic interaction between the hippocampus and the mPFC controls spatial memory in the MWM, and indicate that this cortex is sufficient to retrieve the information essential to reconsolidate the spatial memory trace, even when the hippocampus is inactivated.
Memory Research Laboratory, Brain Institute, Federal University of Rio Grande do Norte, Av. Nascimento de Castro 2155, RN 59056-450, Natal, Brazil.
Janine I
JI
Rossato
Memory Research Laboratory, Brain Institute, Federal University of Rio Grande do Norte, Av. Nascimento de Castro 2155, RN 59056-450, Natal, Brazil.
Cristiano A
CA
Köhler
Memory Research Laboratory, Brain Institute, Federal University of Rio Grande do Norte, Av. Nascimento de Castro 2155, RN 59056-450, Natal, Brazil.
Andressa
A
Radiske
Memory Research Laboratory, Brain Institute, Federal University of Rio Grande do Norte, Av. Nascimento de Castro 2155, RN 59056-450, Natal, Brazil.
Lia R M
LR
Bevilaqua
Memory Research Laboratory, Brain Institute, Federal University of Rio Grande do Norte, Av. Nascimento de Castro 2155, RN 59056-450, Natal, Brazil. Electronic address: martin.cammarota@neuro.ufrn.br.
Martín
M
Cammarota
D000818:Animals; D000841:Anisomycin / Q000494:pharmacology; D058785:GABA-A Receptor Agonists / Q000494:pharmacology; D006624:Hippocampus / Q000187:drug effects*; D008297:Male; D000069077:Memory Consolidation / Q000187:drug effects*; D011939:Mental Recall / Q000187:drug effects*; D009118:Muscimol / Q000494:pharmacology; D017397:Prefrontal Cortex / Q000187:drug effects*; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D065852:Spatial Memory / Q000187:drug effects*
D058785:GABA-A Receptor Agonists; D011500:Protein Synthesis Inhibitors; D009118:Muscimol; D000841:Anisomycin
Anisomycin; Memory; Muscimol; Reactivation; Recall; Water maze