Understanding memory loss: development of a retrieval-induced forgetting paradigm in rodents to model adaptive forgetting in the mammalian brain?.

GALLO FRANCISCO; MICHAEL ANDERSON; MAGDALENA MIRANDA; MORICI FACUNDO; NOELIA V WEISSTAUB; BEKINSCHTEIN, PEDRO

Buenos Aires

Congreso; 2nd Falan Congress; 2016

FALAN- SAN

In the last two decades a growing human literature on retrieval-induced forgetting(RIF) has pointed to inhibitory control processes that resolve retrieval competitionas a cause of adaptive forgetting. However, the lack of animal-basedmodels for RIF has precluded the understanding of the neurobiological mechanisms.Using spontaneous recognition memory in rats, we have successfully developeda rodent paradigm for RIF. We were able to show that forgetting of anitem associated with a particular context happens under conditions that causecompetition between memory traces for two items that share a particular retrievalcue. Under these conditions, forgetting is long lasting and independentof the selected retrieval cue. We used local pharmacological inactivation to showthat this kind of forgetting requires the activity of the medial prefrontal cortex(mPFC) in rats; structure homologous to the human dorsolateral prefrontalcortex (DLPFC). By using c-Fos imaging, we also observed that mPFC activationby retrieval practice occurs only during the rst practice sessions, providing evidencethat, as for humans, rats forgetting is adaptive. These results are consistentwith the idea that the RIF occurs via a top-down inhibitory control mechanismexerted by the mPFC on structures where memory traces may be stored.Our results provide the rst evidence that adaptive forgetting occurs in non-humananimals.