Memory reactivations during sleep: a neural basis of dream experiences?

Memory traces formed during waking hours are spontaneously reactivated during sleep, a phenomenon first observed in the 1990s that has been proposed as the neural basis for dreaming. Recent animal and human studies, along with advances in sleep and dream engineering, show both similarities and differences between memory reactivations and dream experiences. The authors argue that memory reactivations may influence subjective experiences across various states of consciousness but are unlikely to be directly experienced as dreams. They highlight shortcomings in current research methods and propose new approaches to empirically investigate the relationship between memory reactivation and dreaming.

Study at a glance

Abstract

Newly encoded memory traces are spontaneously reactivated during sleep. Since their discovery in the 1990s, these memory reactivations have been discussed as a potential neural basis for dream experiences. New results from animal and human research, as well as the rapidly growing field of sleep and dream engineering, provide essential insights into this question, revealing both strong parallels and disparities between the two phenomena. We suggest that while memory reactivations may contribute to subjective experiences across different states of consciousness, they are not likely to be experienced directly as dreams. We identify important limitations in current research paradigms and suggest novel strategies to address this question empirically.