EEG microstates of dreams

Area of Science:

• Neuroscience
• Sleep Science
• Cognitive Neuroscience

Background:

• Dream recall varies significantly among individuals and even within the same individual.
• The precise brain states governing dream occurrence and the mechanisms preventing awakening during dreams remain largely unknown.

Purpose of the Study:

• To investigate the relationship between electroencephalogram (EEG) microstates during NREM sleep and subsequent dream recall.
• To identify specific brain states associated with the occurrence and recall of dreams.

Main Methods:

• Utilized the EEG microstate approach to analyze transiently stable brain states during sleep.
• Compared EEG microstate dynamics preceding awakenings with reported dream recall versus no recall.
• Employed source localization to identify the brain regions associated with different microstates.

Main Results:

• Two EEG microstates (3 and 4) were more prevalent during NREM sleep compared to wakefulness.
• Microstate 3 was more expressed in periods followed by dream recall, while microstate 4 was less expressed.
• Microstate 3 was localized to the medial frontal lobe, and microstate 4 involved the occipital cortex, thalamus, and brainstem.

Conclusions:

• Increased frontal microstate 3 (deactivation) may contribute to remaining asleep during dreaming.
• Reduced occipital microstate 4 (activation) might facilitate the generation of rich perceptual dream content.
• The temporal dynamics of alternating NREM sleep brain states dictate the emergence of conscious dream experiences.