A retrieval-specific mechanism of adaptive forgetting in the mammalian brain

BEKINSCHTEIN, PEDRO; N. V. WEISSTAUB,; GALLO, FRANCISCO T.; MARIA RENNER; MICHAEL ANDERSON

NATURE COMMUNICATIONS

nature

Año: 2018 vol. 9

2041-1723

Forgetting is a ubiquitous phenomenon that is actively promoted in many species. How andwhether organisms?behavioral goals drive which memories are actively forgotten is unknown.Here we show that processes essential to controlling goal-directed behavior trigger activeforgetting of distracting memories that interfere with behavioral goals. When rats need toretrieve particular memories to guide exploration, it reduces later retention of other mem-ories encoded in that environment. As with humans, this retrieval-induced forgetting iscompetition-dependent, cue-independent and reliant on prefrontal control: Silencing themedial prefrontal cortex with muscimol abolishes the effect. cFos imaging reveals that pre-frontal control demands decline over repeated retrievals as competing memories are for-gotten successfully, revealing a key adaptive benefit of forgetting. Occurring in 88% of therats studied, thisfinding establishes a robust model of how adaptive forgetting harmonizesmemory with behavioral demands, permitting isolation of its circuit, cellular and molecularmechanisms.