Nature and Science of Sleep
January 1, 2022
Raphael Vallat, Başak Türker, Alain Nicolas et al.
People who frequently recall their dreams show greater functional connectivity in the default mode network (DMN) during resting wakefulness and score higher on creativity tests than those who rarely recall dreams. No significant difference in memory abilities appeared between the groups. However, creativity scores did not correlate significantly with DMN connectivity. These findings support the idea that dreaming and mind wandering are related spontaneous mental processes linked to the DMN, and suggest that increased DMN activity may promote creative thinking during both wakefulness and sleep, though causal evidence remains to be established.
Sleep
December 14, 2020
Raphael Vallat, Alain Nicolas, Perrine Ruby
People who frequently recall dreams show distinct brain connectivity patterns immediately after waking compared to those who rarely recall dreams. The study measured brain functional connectivity using combined EEG-fMRI in 20 high dream recallers and 18 low dream recallers before and after an early-afternoon nap. Five minutes after awakening, high recallers exhibited enhanced connectivity within the default mode network and between the default mode network and memory-related brain regions. This connectivity pattern may help maintain the short-term memory of dreams during the transition from sleep to wakefulness. The groups differed in dream recall but not in recall of a comic presented before the nap.
Frontiers in Neurology
January 1, 2020
Alain Nicolas, Perrine Ruby
A review of experimental results from the past 60 years finds that most antidepressant drugs reduce dream recall frequency, and improvement in depressive symptoms is linked to more positive emotions in dream content. Sedative psychotropic drugs also reduce dream recall frequency by improving sleep quality, but their effect on dream content is unclear. Nightmare frequency can increase with sleep-disrupting molecules or withdrawal of some psychotropic drugs. The impact of these drugs on REM sleep does not explain changes in dream recall frequency; instead, reducing intra-sleep awakenings best accounts for the reduction in dream recall, consistent with the arousal-retrieval model. Other factors like interest in dreams, awakening method, and personality traits also influence variability in results.
Journal of Sleep Research
October 1, 2018
Raphael Vallat, Mickael Eskinazi, Alain Nicolas et al.
French college students spend about 8 hours in bed on weekdays and 9 hours on weekends, with 90.9% reporting no difficulty falling asleep. Dream recall averages about 3 mornings per week, positively linked to dream clarity and lucid dreaming frequency, and negatively linked to age. Nearly 7% report regular sleep-talking, while less than 0.4% have regular sleepwalking. Frequent lucid dreams occur in 14% of students, and recurrent dreams in 6%. Women report higher dream recall and more time in bed than men. Humanities students spend more time in bed than science students, suggesting a link between academic discipline and sleep duration.
Frontiers in Psychology
January 1, 2018
Raphael Vallat, Jean-Baptiste Eichenlaub, Alain Nicolas et al.
People who frequently recall dreams have denser white matter in the medial prefrontal cortex (MPFC) than those who rarely recall dreams. Using brain scans of 46 high dream recallers (who recalled dreams about six mornings per week) and 46 low dream recallers (who recalled dreams less than once per week), researchers found no differences in gray or white matter density in the temporo-parietal junction, hippocampus, or amygdala. The finding aligns with evidence that damage to MPFC white matter can stop dream reporting, suggesting this region plays a role in dream recall or production.
Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology
June 1, 2014
Jean-Baptiste Eichenlaub, Alain Nicolas, Jérôme Daltrozzo et al.
People who frequently recall dreams show higher blood flow in two brain regions—the temporoparietal junction (TPJ) and the medial prefrontal cortex (MPFC)—both during sleep and while awake, compared with people who rarely recall dreams. High recallers averaged 5.2 dream recalls per week, low recallers 0.5. The findings support the idea that these parts of the default mode network are involved in producing and encoding dreams, not just in recalling them after waking. Increased TPJ activity may also help orient attention to external stimuli and promote brief awakenings that aid memory encoding.