Not the same as it ever was: A review of memory modification, updating, and distortion in humans and rodents

Memory is a reconstructive and continuous process that enables existinginformation to be updated in response to a changing environment. Being able to dynamicallyupdate outdated memories is critical to an organism’s survival. Memory updates ormodifications have been extensively studied within the context of a variety of conceptualmodels in both rodents and humans, but these diverse bodies of literature have not yet beenfully integrated into a comprehensive cross-species review uniting regional, cellular,neurotransmitter, and subcellular molecular mechanisms. Integrating the findings acrossrodent and human work is important for developing a comprehensive understanding of howmemory modifications are encoded and retrieved and crucial to revealing similarities anddifferences in the methods, behavioral findings, and underlying neural mechanisms thatsupport memory modification in both humans and rodents.Here, we discuss advances in our understanding of adaptive (memory updating) andmaladaptive (memory distortion) memory modification in terms of both underlyingmechanisms (regional, cellular, and molecular) and behavioral outcomes. By emphasizingfindings from both humans and rodents, the two major model systems in which memorymodifications have been studied, we are able to highlight converging mechanisms and pointto open questions in the field. Specifically, we discuss the major findings from severalmemory paradigms including declarative, aversive and procedural memory designs andhighlight paradigms and models that have been readily translated between rodent andhuman models. Ultimately, this review identifies key parallels underlying memory updatingacross species, paradigms, tasks, and models.