Understanding memory loss: Development of a retrieval-induced forgetting paradigm in rodents

GALLO FRANCISCO; ZANONI SAAD MARIA BELEN; MAGDALENA MIRANDA; BEKINSCHTEIN, PEDRO; MORICI FACUNDO; WEISSTAUB, NOELIA

Mar del Plata

Congreso; XXXII Reunion Anual de la Sociedad Argentina de Investigaciones en Neurociencias; 2017

SAN

In the last two decades there ́s been a growing human literature on a phenomenon called retrieval-induced forgetting (RIF). RIF has pointed to inhibitory control processes that resolve retrieval competition as a cause of adaptive forgetting. Using spontaneous recognition memory in rats, we have developed a rodent paradigm for RIF. We were able to show that forgetting of an item associated with a particular context happens under conditions that cause competition between memory traces for two items that share a particular retrieval cue. Under these conditions, forgetting is long lasting and independent of the selected retrieval cue. We used local pharmacological inactivation to show that this kind of forgetting requires the activity of the medial prefrontal cortex (mPFC). With pharmacological inactivation, we showed that the Ventral Tegmental Area (VTA) is necessary for the forgetting to occur and that the infusion of a D1/5 agonist in the mPFC is sufficient to rescue the expression of the RIF phenomenon impelled by the inactivation of the VTA. These results are consistent with the idea that the RIF occurs via a top-down inhibitory control mechanism exerted by the mPFC on structures linked by hypothesized memory traces. With the latter results, we bring new evidence supporting the role of dopamine in the resolution of interference via mPFC inhibitory control.