The neural correlates of dreaming.
Level 4 - case-series / case-control
Observational within-subject neuroimaging study (graded by design analogy for basic cognitive neuroscience)
PubMed 28394322 · doi:10.1038/nn.4545
What was done
High-density electroencephalography (hd-EEG) was recorded during both non-rapid eye movement (NREM) and rapid eye movement (REM) sleep. Brain activity was compared between awakenings where participants recalled dream experiences and awakenings where they recalled no conscious experience. Investigators also evaluated whether real-time hd-EEG monitoring of posterior cortical activity could predict the presence or absence of dream reports upon waking from NREM sleep.
What was found
The abstract does not report sample sizes, specific numerical values, or statistical effect sizes. Qualitatively, reports of dream experiences in both REM and NREM sleep were associated with local decreases in low-frequency EEG activity in posterior cortical regions. High-frequency activity in these posterior regions correlated with specific dream contents, and real-time monitoring of this posterior region predicted whether participants reported dreaming or no experience during NREM sleep.
Why it matters
This study identifies a localized posterior cortical signature associated with conscious experience during sleep across both REM and NREM states, challenging the view that dreaming requires global, wake-like REM activation.
Limits
The abstract provides no details regarding participant sample size, age, sex, number of sleep awakenings, or prediction accuracy metrics. Reliance on retrospective dream recall upon awakening introduces potential memory and reporting biases.
Cited by
- context During early stages of sleep, humans enter non-REM delta wave sleep where conscious self-experience is absent, whereas later stages involve dreaming.