A Retrieval-Specific Mechanism of Adaptive Forgetting in the Mammalian Brain

BEKINSCHTEIN, PEDRO; WEISSTAUB, NOELIA V.; GALLO, FRANCISCO; MARÍA RENNER; MICHAEL ANDERSON

NATURE COMMUNICATIONS

Springer Nature

Año: 2018

2041-1723

Forgetting is a ubiquitous phenomenon that is actively promoted in many species. How and whether active forgetting mechanisms are driven by adaptive behavior is unknown. Here we show that control processes that enable flexible behavior in rats promote adaptive forgetting of traces that hinder retrieval of memories needed to guide behavior. We found that when animals retrieved their prior experience with an object to guide new exploration, it significantly reduced their later recognition of other objects previously encountered in that environment. Consistent with similar findings in humans, this retrieval-induced forgetting was competition-dependent, cue-independent, long-lasting, and reliant on control processes mediated by the prefrontal cortex. Silencing the medial prefrontal cortex with muscimol selectively abolished the forgetting effect. cFos imaging revealed that prefrontal control demands declined over repeated retrievals as competing memories were forgotten, revealing a key adaptive benefit of forgetting This finding establishes an unusually robust model of how adaptive forgetting harmonizes the mnemonic ecosystem with behavioral demands, and permits isolation of its circuit, cellular and molecular mechanisms.