Brain functional connectivity upon awakening from sleep predicts interindividual differences in dream recall...

Area of Science:

• Neuroscience
• Sleep Science
• Cognitive Psychology

Background:

• Individual differences in dream recall are significant, yet the underlying mechanisms remain unclear.
• Sleep inertia, a post-awakening state of cognitive impairment, is hypothesized to influence dream recall.
• Understanding these differences is crucial for sleep and memory research.

Purpose of the Study:

• To investigate the relationship between brain functional connectivity during sleep inertia and interindividual differences in dream recall.
• To explore the role of the default mode network (DMN) and memory-related regions in dream recall.
• To compare cognitive performance and recall abilities between high and low dream recallers.

Main Methods:

• Combined electroencephalography-functional magnetic resonance imaging (EEG-fMRI) was used to measure brain functional connectivity.
• Participants included high dream recallers (HR) and low dream recallers (LR) after an early-afternoon nap.
• Cognitive tasks (memory, mental calculation) and recall of dreams and a presented comic were assessed post-awakening.

Main Results:

• High dream recallers showed enhanced functional connectivity within the default mode network (DMN) and between the DMN and memory regions 5 minutes post-awakening.
• A significant difference in dream recall was observed between HR and LR groups.
• No significant difference in comic recall was found between the groups, suggesting specificity to dream content.

Conclusions:

• Brain functional connectivity immediately following awakening is associated with individual differences in dream recall.
• Enhanced connectivity in HR may facilitate the short-term memory consolidation of dreams during the sleep-wake transition.
• Sleep inertia's impact on brain connectivity offers a potential mechanism explaining variations in dream recall.