Exploring the neural correlates of dream phenomenology and altered states of consciousness during sleep

Dreaming occurs during both rapid eye movement (REM) and non-REM sleep, but the phenomenological characteristics differ between these stages. Lucid dreaming, where the dreamer is aware they are dreaming, offers a unique window into consciousness during sleep. The review synthesizes previous literature on brain activity across the sleep cycle, showing how neurofunctional changes relate to variations in dream content and the level of consciousness experienced. The authors aim to clarify how these neural shifts may underlie the subjective qualities of dreams.

Study at a glance

Abstract

The science of dreaming constitutes a relevant topic in modern-day neuroscientific research and provides major insights into the study of human consciousness. Linking specific, universal, and regularly occurring stages of sleep with dreaming encourages the direct and systematic investigation of a topic that has fascinated humankind for centuries. In this review, we explore to what extent individuals dream during periods of rapid eye movement and non-rapid eye movement sleep, and we introduce research on lucid dreaming. We then discuss how dreaming during different stages of sleep varies in terms of phenomenological characteristics, and to what extent individuals are conscious throughout the sleep cycle. Finally, we provide a synopsis of the previous literature on brain activity during sleep, and we aim to clarify how the neurofunctional changes observed throughout sleep may lead to changes in phenomenological aspects of dreams, and in the domain of consciousness.