The transience and persistence of memory: Linking neurobehavioral mechanisms of adaptive forgetting to adult aging and mood

In cognitive models of memory, forgetting is most often treated as a failure to encode, maintain, or retrieve information. It has been hypothesized to result from various processes including interrupted consolidation, passive decay, interference, and retrieval failure. However, remembering a past experience can, quite surprisingly cause forgetting, and forgetting may be imperative to efficient remembering. Thus, an efficient memory system depends both on the ability to intentionally encode and store relevant information over time (i.e. persistence), but also to intentionally forget irrelevant information (i.e. transience). Critically, an inability to remove outdated and irrelevant information from memory may be an underlying cause of memory failures in older age, and may also contribute to mood disorders that involve ruminating and re-experiencing negative and unwanted thoughts and memories.

Much information has been gained from behavioral studies on human memory. However, behavioral methods are, by their nature, blind to the internal processes accompanied by a retrieval episode. Using neuroimaging methods could thus contribute to building theoretical models of memory functions in general, and, more specifically, of adaptive forgetting. The overall purpose of the present project is to elucidate the neurobehavioral mechanisms of adaptive forgetting and examine how such processes are related to memory deficits in adult aging and mood. In part 1 of this research program we will use novel behavioral paradigms in conjunction with functional magnetic resonance imaging (fMRI) to investigate age-differences and neural mechanisms underlying adaptive forgetting in working memory (WM) and episodic memory. In part 2, we aim to validate the link between individual differences in controlling ones thoughts, memories and emotions, to neurobehavioral indicators of adaptive forgetting.

Specific aims:

• To validate models of age-differences in adaptive forgetting in WM
• To examine if retrieval can induce adaptive forgetting of competing episodic memories, and if such processes are affected by increasing age
• To determine if adaptive forgetting is related to regulation of mood and anxiety

This project is funded by a grant from the Swedish Research Council (Vetenskapsrådet).